Hi Richard, Did you ever figure this out? I'm facing the same issue. When I "Register Payment" for a few Vendor Bills, I'm sometimes able to get it all on one payment, but sometimes the system forces 2 separate payments. I've double checked that it's really the same vendor being selected. One thing I noticed is that in the case of successful single payment, upon clicking the "Group payments" checkbox, I get a slightly more detailed wizard asking me to key in the bank account. For the case where 2 separate payments were made, I did not get this detailed wizard. Hope someone can shed light on this!

Hello

If you want to create one payment it must be for the same customer not two different customers in multi invoices , so you can use option group payment but first you need to active it from accounting module settings