It is possible and I'm sure there are many ways to do it.
From L2 (connectivity) point of view, you can use separate VLANs to separate different networks (WAN v.s. LAN) passing the same wire.
From L3 point kf view, you may want to consider if firewalling the WAN-addressed virtual server should be done or not. If yes, does it have to use public IP address or can it have a private one and router would perform NAT (for specific public address) or even netmap (1:1 of all ports).