PO Release strategy

Hi SAP Gurus

I have two differnt PO release strategy for 2 company codes.As we can use a single class for PO.whatever the characteristics defined for one relesae strategy ,the same are reflected for the other.

Now my problem is that for one release strategy i m using 'Cost centre' as a charateristics & it is notrequired for other.

But in relesae strategy whre 'Cost centre' is not required, i have to maintain the values in release stretgy & inwhile creating PO..Plesae tell me ,is there any option for that whre same class is in use.

please help me.