multible networks routing over vpn tunnel

[thomas may]

hello,
 
i have two private network segments, 192.168.0.x and 192.168.1.x connected
over a VPN Tunnel, freebsd, racoon and ipsec.
on one site we want to add a new network segment 192.168.3.x
 
is this possible and how is the correct syntax ?
 
this is what i have done:
 
gifconfig gif0 A.B.C.D W.X.Y.Z
ifconfig gif0 inet 192.168.1.1 192.168.2.1 netmask 255.255.255.0

# gifconfig gif0
gif0: flags=8011<UP,POINTTOPOINT,MULTICAST> mtu 1280
inet 192.168.0.1 --> 192.168.1.1 netmask 0xffffffff
physical address inet A.B.C.D --> W.X.Y.Z

 
regards thomas