Condition in PR work flow with the combination GL account and cost center in AX 2009

Hi,

In AX 2009

If we want to set conditions which are combination of Ledger account and cost center, How to do? Assume that there is already workflow with some other conditions.

Then what would be the impact on system performance?

If we use the mentioned work flow condition, what will happen if user enter GL and CC combination which is not defined in the work flow?

Please consider the number of conditions which should be defined in the system will be too much.

Thanks,

Manju