3 machines with no hub or switch?
Hmmm.... I'm not aware of any "bridging" software for Win 95 so here goes:
You could try this solution since you have Win 95 which doesn't have native routing capability like NT - Load up a "routing" program such as WinRoute Lite (
http://www.winroute.com) and have ONE PC with 2 NICs be the router with the other two PCs connected via crossover cables to each NIC. Don't know how that would work with your games, but theoretically it should do fine.
..and yes, you can mix ISA and PCI NICs as long as you have enough IRQs to go around!