Privacy: Transfer balances away from xpubs

[coolaj86]

It's only a pretense, but I don't want my friends to be able to directly see whether or not I've spent the money they sent (by indexing the xpub I gave them).

Instead, once money comes in, it should transfer to one of my other wallets - perhaps a 3rd, non-shared wallet still associated with the contact, in order to trace which transactions they can easily see (any tx with a coin from their xpub colors that tx as a tx they can see).