Unless you get a second IP from the ISP, well, any connection you see today means one may see the other.
To me this is one odd request as network shares and such can be access controlled. Access control this way can be done (get the second IP) but I wonder if you'll balk at the cost.
I have one cable modem and two routers from different manufacturers; Netgear and Linksys. My main router is the one from Netgear which is fine the way it is but I would like to add a second router from Linksys to be into another network separated from the main one for my lab. How can I add this second router in a way they won't be seen each other?
Thanks for your help!