Site to Site VPN connecting to another network

[mrkim]

I am a newbie on this. I have setup a Site (A) to Site (B) VPN with 2 routers. I am using a 192.168.1.x on site (A) and a 192.168.2.x on Site (B). I would like to connect Site (B) router to a different network 20.0.0.1 (C) so that side (A) can talk to site(C) running though Site (B)

Any help on how to set this up?

 

[ROUTERKID1]

what kind routers and what type of connection ?

 

[mrkim]

I left that out.. They are Avaya SG5 routers