Connecting 2 differents network

My initial stab at this is you need another router which is connected to both 192 networks. From the router which provides internet connectivity for both 192 networks, you need to put in a static route which points to the other 192 network with the gateway being the new router which routes between the two of the 192 networks.

For instance, for the 192.168.10.x network, assuming the new router has an IP of 192.168.10.2, you would set a static route on the default router of this network (assuming it is 192.168.10.1) to say to get to network 192.168.1.0/24 (assuming class C) use 192.168.10.2 as your gateway. For the 192.168.1.x network you will do the same but in the opposite direction with a static route in your default gateway for 192.168.10.0/24 with a gateway of 192.168.1.2.

This isn't the best way to do it, but it'll work. You'll also have to make sure any router you put in between the two networks is a pure router or if you're after using a SOHO router, make sure the SPI firewall is turned off. If you want to limit the traffic between the two networks via ACLs, then this will open up a whole other discussion which will get more complex and probably require more expensive hardware.