If the file-names come to you in alphabetical order, as they most-commonly do, then all occurrences of baz.anything will necessarily be consecutive.

This is not something one should rely on, it varies wildly depending on OS and API used to list the files. And even if one sorted the list, it would not help for the OP's second requirement, "some 'dups' might have minor variations in characters".

Oops, didn't see Corion's node before posting.