A crude mechanical ethernet switch

This "switch" is not a "real" switch, in the normal context of this forum, but I'm not aware of anything that would do this function, namely select one of several input/outputs to go to a common output/input.  And ignore the not selected ones.

I currently have 3 independent tunneled AREDN networks here.  (the people I'm tunnel clients to wanted me to isolate them from the others).  Anyway, I tried to have my PC connect to each with separate NICs.  Problem is, I could connect to services on one AREDN network, but not others.  Seems the PC gets confused as to which AREDN network stuff in the IP address range 10.x.x.x a particular IP address belongs to which NIC to its AREDN network.  If I want to connect to 10.a.b.c  via AREDN network 1, I might get lucky and the computer picks the correct NIC to pipe it thru.  But If I want to go to 10.a.f.g and that is on AREDN network 2, seems the computer pipes it to the NIC connecting to AREDN network 1 and I fail to find it.  And if I want something on AREDN network 3, at say 10.h.j.k the PC will also try to pipe it to AREDN network 1 and again it fails.  Seems the PC can't split up the 10.x.x.x IP range into multiple NIC connections, especially if the IP address are not in contiguous blocks.   My ISP connection is via 192.169.1.x, so stuff on the Internet is always reachable. No confusion there.  

A crude solution to have the PC be able to connect to stuff on each AREDN network was to build a mechanical switch to select which AREDN node LAN to connect the PC to.  This makes sure that I can access stuff on a specific AREDN network (but only that one until I change the switch setting). 

I'm a hardware guy, software guys might be able to solve this problem more elegantly.  Seems ethernet is fairly forgiving of impedance bumps caused by my switch.  I did twist each pair to attempt to maintain twisted-pair-ness inside my switch box.  This box was originally a 4 way VGA monitor switch box, but inside it was just a mess of loose wires.  I only used 4 of the 15 poles of this switch, the leftover poles I left connected to the original VGA connectors inside the box.  If I should need to hook up the brown and the blue twisted pairs, I did only the green and orange pairs.