Multiple Forticlient VPN on a Single Interface - Is it possible?

Running 5.6.12

I have successfully been running a "Forticlient" IPSec VPN on my public facing interface, it's for staff remote access.

I need to have a 2nd "Forticlient" IPSec VPN on the same public interface so I can isolate traffic for different staff, then having different policy and access to different internal subnets.

I can only get the 2nd "Forticlient" IPSec VPN to connect if I move it to another public interface. I cannot get it to connect on the same interface as the existing one. Is this a known limitation or am I just having issues with config, Forticlient version etc?

Client OS is Win10 and or Win7.

Appreciate any and all help, cheers!

 (O0)