Hi. Very much a novice here.
I need helt to make a quick and easy rule that only allows certain IP-adresses to communicate over an IP-bridge.
I'm using the routers to add a firewall at certain points in a very spread out network for a housing company.

Not quite sure what you mean but have you tried forward chain IP firewall filter rules? They manage traffic just fine 98% of the time.
If they do not work there is such a thing as Bridge firewall rules - but they are for advanced users and unique circumstances

Not quite sure what you mean but have you tried forward chain IP firewall filter rules? They manage traffic just fine 98% of the time.
If they do not work there is such a thing as Bridge firewall rules - but they are for advanced users and unique circumstances

The network is spread across a city and lacks firewall. I need to add routers solely to add firewall at specific points in the network. The only traffic on the router will be over an ip-bride on two ports. I need to limit the traffic allowed so that only traffic from specific IPs is passing over the bride.

I see the need for a clear drawing because the textual explanation is really not clarifying at all ...