diff --git a/optimas/gen_functions.py b/optimas/gen_functions.py
index 7879a7e7..d13c209f 100644
--- a/optimas/gen_functions.py
+++ b/optimas/gen_functions.py
@@ -96,6 +96,7 @@ def persistent_generator(H, persis_info, gen_specs, libE_info):
             # Check how many simulations have returned
             n = len(calc_in["sim_id"])
             # Feed the latest simulation results to the generator
+            trials = []
             for i in range(n):
                 trial_index = int(calc_in["trial_index"][i])
                 trial_status = calc_in["trial_status"][i]
@@ -107,8 +108,11 @@ def persistent_generator(H, persis_info, gen_specs, libE_info):
                         y = calc_in[par.name][i]
                         ev = Evaluation(parameter=par, value=y)
                         trial.complete_evaluation(ev)
-                # Register trial with unknown SEM
-                generator.tell_trials([trial])
+                trials.append(trial)
+
+            # Register trials with unknown SEM
+            generator.tell_trials(trials)
+
             # Set the number of points to generate to that number:
             number_of_gen_points = min(n + n_failed_gens, max_evals - n_gens)
             n_failed_gens = 0
diff --git a/optimas/generators/__init__.py b/optimas/generators/__init__.py
index 237fb921..4a74b424 100644
--- a/optimas/generators/__init__.py
+++ b/optimas/generators/__init__.py
@@ -22,7 +22,7 @@
 from .grid_sampling import GridSamplingGenerator
 from .line_sampling import LineSamplingGenerator
 from .random_sampling import RandomSamplingGenerator
-
+from .external import ExternalGenerator
 
 __all__ = [
     "AxSingleFidelityGenerator",
@@ -32,4 +32,5 @@
     "GridSamplingGenerator",
     "LineSamplingGenerator",
     "RandomSamplingGenerator",
+    "ExternalGenerator",
 ]
diff --git a/optimas/generators/external.py b/optimas/generators/external.py
new file mode 100644
index 00000000..8cb71e1c
--- /dev/null
+++ b/optimas/generators/external.py
@@ -0,0 +1,25 @@
+"""Contains the definition of an external generator."""
+
+from .base import Generator
+
+
+class ExternalGenerator(Generator):
+    """Supports a generator in the CAMPA generator standard."""
+
+    def __init__(
+        self,
+        ext_gen,
+        **kwargs,
+    ):
+        super().__init__(
+            **kwargs,
+        )
+        self.gen = ext_gen
+
+    def ask(self, n_trials):
+        """Request the next set of points to evaluate."""
+        return self.gen.ask(n_trials)
+
+    def tell(self, trials):
+        """Send the results of evaluations to the generator."""
+        self.gen.tell(trials)