If you have the advanced version you should try setting them up as two stereo pairs in Hauptwerk. Put each pair in a primary bus mixer channel and make a group which includes these two primary buses. Assign the group you have created as the output for each rank output perspective 1. Use Haupwerk’s cyclic algorithm so the output is shared across the two stereo channels.
Have a look at my tutorials if you need more info than the manual (https://iainstinson.com/hauptwerk/).
Iain