multiple instances of vpn server

Hello,

I have a single server with 4 interfaces, two external and two internal, 
which serve as a gateway to two separate internal networks.

At present I have a single VPN server listening on a single external 
interface and serving a single internal network.

Is it possible to have two instances of the VPN server, listening on 
separate extenal interfaces and serving separate internal networks?

Thanks,
Clemente

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