Why two payment document number in FPY1

Hi Experts,

When I am collecting the payment at business partner level in transaction FPY1, it create two payment document number according to contract account.

As there are two contract account under that business partner and there are two separate debit line item for that two contract account each. And when I run FPY1 it create two payment document number according to contract account.

But we have maintain the grouping rule for business partner also in spro.

Please suggest, so that we can provide the solution to our clients.

Thanks & Regards

Tamal