If the thinlinc server requires you to connect to 192.168.1.1
A static host route could solve the problem. This is not a scalable solution but might work for you.
In this setup i don’t think you need to enable IP forwarding on the thinlinc server.
A better way is to setup split DNS. The short version is that if your thinlinc servers is named “thinlinc”. Clients on 192.168.1.0 network should resolve “thinlinc” to 192.168.1.1 and the clients on the 192.168.2.0 network should resolve thinlinc to 192.168.2.1. This can be done in a single DNS server. Google “split dns”