So basically your are looking for a way to apply firewall filters based on AD Group membership? Something as FSAE/FSSO in Fortinet workd?
The way I have it working now is a different OpenVPN server and access server per security group but I don't want to make new OpenVPN and access servers if I need to create a new AD group...Is it even possible to do with OPNsense in a better more scalable way?