configure OBA7 based on company code

Hi Gurus

heres my problem.

in OBA7-- in "required during document entry tab", the check box for reference number is ticked.

but i want that to be set up based on company code.

for 1 company code, they want it to be not required, where as others want it.

Please let me know is there a way i can do this, the same set up where i can even enter company code.

also let me know is its a problem to uncheck it.

Thanks a lot

kavana