Cutomize Standard Oracle Procedures

Hi

I have a requirement in Payable. In my company, there are 3 types of accounts payable responsibility. One group who does payament for employees and other who does the payment for general vendors. For this a batch naming conventions was invented and other security is build up within Invoice and Payment module

Now the issue is each group should post only the batches related to them. So does Oracle support customization of 'Payable Accounting Process' and 'Payables Transfer to General Ledger'.  Else is there any other solution?

Thanks & Regards
Neelima