Credit Labor Billing AAIs - not enough criteria?

Wondering if anyone else has had an issue regarding needing more criteria field to drive the Credit Labour Billing offset account besides HMCU and MCUO.   I have, for example, Employee A (HMCU = XXXXXX) and in time entry, he keys MCUO= YYYYYYY.    He needs his credit offset account for this time to hit XXXXXX.12345.AAAAAAA

However, Employee B (HMCU = XXXXXX) and in time entry keys MCUO = YYYYYY.  He needs his credit offset account for this time to hit XXXXXXXX.12345.BBBBBBBB

I have not found any way that this can be done without modifying standard or creating an override after pro forma batch is created.