sort by characters within cell

I have a column that contains an ID number in the form of "AA123-123456". I'd like to put a combox in the sheet with some code behind it that will sort the whole sheet by this column using either the full ID number, or alternatively the 6 digits that come after the dash. The AA123 may not be a fixed number of characters, but the numbers after the dash will stay fixed at 6 numbers long.

Any help?