ROUTING QUESTIONS, MULTIPLE SUBNETS TO ACCESSS COMMON SOURCE, HELP!

[JoshIE490]

I have 3 people working remotely from one location. Each person connects via vpn on their own subnet and wan IP.

subnet #1
192.168.5.0\24

subnet #2
192.168.10.0\24

subnet #3
192.168.15.0\24

what I have done is introduced another linksys router to create a common shared subnet #4:

192.168.20.0\24

I want to attach the 4 printers we use to subnet #4 as well as 2 tivo boxes and a 1TB network share drive for video editing.

How can I setup routing that each subnet can access the resources on 192.168.20.0\24, and only those shared resources. Keeping each subnet(1,2,&3) a private network, not disturbing vpn tunnels,domains, and remote access for 1,2, and 3.

Is it possible for #1,#2, and #3 to only see #4. This routing solution would allow us to share all printers and digital video applications, as well as keep us private and secure.

Any help and all suggestions are greatly appreciated

thanks, Josh