I'm trying to learn how to have two completely segregated networks USING one Internet connection.

I have two routers, both of which are also DSL transceivers. However, neither has guest networking, and the firewall each provides doesn't allow me to filter LAN-to-LAN traffic and thus create two segregated networks. So I'm trying to use both routers at once to accomplish the task.

It's important that no machine connected to either ROUTER can communicate with a machine on the other.

This is what I've managed to gather so far:

Router 1 --> Router 2 --> Internet
Router 1 is configured to be a bridge
Router 1 is configured with a static WAN address, that address being part of Router 2's LAN subnet
Router 1 is configured to have an ethernet port act as a WAN(uplink) port (My routers don't have dedicated uplink PORTS)
Router 1's WAN(uplink) port is connected to a LAN ethernet port on Router 2
Router 1 and Router 2 are configured to use different SUBNETS when providing IP addresses for connected machines

Is this going in the right direction? Are the networks completely segregated at this point?

Also, both routers have the ability to specify a single ethernet port for VLAN use. However, I'm not sure if/how that comes into play.

Thank you for any help on the matter.If your routers support the feature, look into configuring VLAN for your network.

This will complete the requirement of the two sets of machines not being able to talk to each other, as well as allowing you to set a default gateway in the routers to provide Internet access to both VLANs

Are you using Cisco hardware?

EDIT: Also yes, if the two LANs are configured on separate subnets then they are segregated already, however if your routers are configured with a routing protocol that has network advertising enabled then the routing table will automatically populate and the two networks will be routed to each other.