diff --git a/lib/openhab/core/items.rb b/lib/openhab/core/items.rb
index 09e3fbf70..5482daeff 100644
--- a/lib/openhab/core/items.rb
+++ b/lib/openhab/core/items.rb
@@ -74,13 +74,17 @@ def def_command_methods(klass)
               RUBY
 
               Enumerable.class_eval <<~RUBY, __FILE__, __LINE__ + 1
-                def #{command}         # def on
-                  each(&:#{command})   #   each(&:on)
-                end                    # end
-                                       #
-                def #{command}!        # def on!
-                  each(&:#{command}!)  #   each(&:on!)
-                end                    # end
+                ruby2_keywords def #{command}(*args, &block)    # ruby2_keywords def on(*args, &block)
+                  each do |member|                              #   each do |member|
+                    member.#{command}(*args, &block)            #     member.on(*args, &block)
+                  end                                           #   end
+                end                                             # end
+                                                                #
+                ruby2_keywords def #{command}!(*args, &block)   # ruby2_keywords def on!(*args, &block)
+                  each do |member|                              #   each do |member|
+                    member.#{command}!(*args, &block)           #     member.on!(*args, &block)
+                  end                                           #   end
+                end                                             # end
               RUBY
             else
               logger.trace { "Defining #{klass}/Enumerable##{command} for #{value}" }
diff --git a/lib/openhab/core/items/group_item.rb b/lib/openhab/core/items/group_item.rb
index 71372df9e..ce4a5b4cc 100644
--- a/lib/openhab/core/items/group_item.rb
+++ b/lib/openhab/core/items/group_item.rb
@@ -199,7 +199,10 @@ def type_details
         end
 
         # Delegate missing methods to {base_item} if possible
-        def method_missing(method, *args, &block)
+        # Command methods and predicate methods for GroupItem are performed here
+        # instead of being statically defined in items.rb
+        # because base_item is needed to determine the command/data types but is not available in the static context
+        ruby2_keywords def method_missing(method, *args, &block)
           return base_item.__send__(method, *args, &block) if base_item&.respond_to?(method) # rubocop:disable Lint/RedundantSafeNavigation nil responds to :to_a
 
           super
diff --git a/spec/openhab/core/items/group_item_spec.rb b/spec/openhab/core/items/group_item_spec.rb
index e18fb6f23..aef7fb11f 100644
--- a/spec/openhab/core/items/group_item_spec.rb
+++ b/spec/openhab/core/items/group_item_spec.rb
@@ -122,6 +122,16 @@
     end
   end
 
+  it "supports command methods" do
+    items.build do
+      group_item "Switches", type: :switch do
+        switch_item "SwitchOne"
+      end
+    end
+
+    Switches.on
+  end
+
   describe "#method_missing" do
     it "has command methods for the group type" do
       items.build do
diff --git a/spec/openhab/dsl/items/builder_spec.rb b/spec/openhab/dsl/items/builder_spec.rb
index 142d41198..5ac7010e6 100644
--- a/spec/openhab/dsl/items/builder_spec.rb
+++ b/spec/openhab/dsl/items/builder_spec.rb
@@ -604,7 +604,7 @@ def build_and_update(org_config, new_config, item_to_keep: :new_item, &block)
   end
 
   it "sets initial state on a group item" do
-    items.build { group_item "GroupItem1", type: "Switch", state: ON }
+    items.build { group_item "GroupItem1", type: :switch, state: ON }
     expect(GroupItem1.state).to be ON
   end
 
diff --git a/spec/openhab/dsl/items/timed_command_spec.rb b/spec/openhab/dsl/items/timed_command_spec.rb
index 772826dc2..7ad6b681d 100644
--- a/spec/openhab/dsl/items/timed_command_spec.rb
+++ b/spec/openhab/dsl/items/timed_command_spec.rb
@@ -291,13 +291,49 @@ def self.test_it(initial_state, command)
     expect(manualitem.state).to eq OFF
   end
 
-  it "works with GroupItem" do
-    items.build { group_item "Group1", type: "Switch", autoupdate: true }
-    Group1.update(OFF)
-    Group1.command(ON, for: 1.second)
-    expect(Group1).to be_on
-    time_travel_and_execute_timers(2.seconds)
-    expect(Group1).to be_off
+  context "with GroupItem" do
+    it "works" do
+      items.build do
+        group_item "Group1", type: :switch do
+          switch_item "Switch1"
+        end
+      end
+      Group1.command(ON, for: 1.second)
+      expect(Group1).to be_on
+      time_travel_and_execute_timers(2.seconds)
+      expect(Group1).to be_off
+    end
+
+    it "works in command methods" do
+      items.build do
+        group_item "Group1", type: :switch do
+          switch_item "Switch1"
+        end
+      end
+      Group1.on for: 1.second
+      expect(Group1).to be_on
+      time_travel_and_execute_timers(2.seconds)
+      expect(Group1).to be_off
+    end
+
+    it "cancels implicit timer when its group member received a command" do
+      items.build do
+        group_item "Group1", type: :number, function: "AVG" do
+          number_item "Number1", state: 0
+        end
+      end
+      Group1.update(0)
+      Group1.command(1, for: 1.second)
+      expect(Group1.state).to eq 1
+      time_travel_and_execute_timers(2.seconds)
+      expect(Group1.state).to eq 0
+
+      Group1.command(1, for: 1.second)
+      Number1.command(2)
+      expect(Group1.state).to eq 2
+      time_travel_and_execute_timers(2.seconds)
+      expect(Group1.state).to eq 2
+    end
   end
 
   context "with Enumerable" do
@@ -317,6 +353,15 @@ def self.test_it(initial_state, command)
       expect(Switch2).to be_off
     end
 
+    it "works with command methods" do
+      [Switch1, Switch2].on for: 1.second
+      expect(Switch1).to be_on
+      expect(Switch2).to be_on
+      time_travel_and_execute_timers(2.seconds)
+      expect(Switch1).to be_off
+      expect(Switch2).to be_off
+    end
+
     it "each member has its own timer" do
       [Switch1, Switch2].command(ON, for: 1.second)
       Switch1.on