Concatenate or Substitute from multiple sheets/columns with wildcard validation?

I have nice large set of data that I'm trying to condense into fewer rows/columns. It's a product list from a mfg. I need to condense the products into categories. Easy? No, because this is how the data is presented:

Sheet 1 - Actual part #'s:
ABC123A.123
ABC123B.123
ABC123C.123
ABC123A.456
ABC123B.456


Sheet 2 defines the category and a generic product number ("x" is the wildcard):

Category	Part #
CATEGORY A	ABC123x.123
CATEGORY B	ABC123x.456

I need to find a way to pull the data from Sheet 1,Column A and display it on Sheet 2 in one cell in Column B.

Ultimately this is what I'd like the end result to be:

Category	Part #'s (Separated by ",")
CATEGORY A	ABC123A.123,ABC123B.123,ABC123C.123
CATEGORY B	ABC123A.456,ABC123B.456

Does this explanation make sense and is it possible?