Networking help again

[oj88]

You can turn on the DHCP on router 3 but assign it a different IP group/range.

Example:
Router1 group: 192.168.1.X
Router2 group: 192.168.2.X
Router3 group: 192.168.3.X

Also on router 3, simply assign the IP address of router 1 as it's gateway.

This would let any PCs connecting to router 3 to get a "local" IP (from router 3) yet still get internet from router 1.

Just a note. If you're using a 24-bit mask (255.255.255.0) which is usually the default subnet mask on most router's LAN configuration, that won't work. You need to use a 22-bit masks or lower.