I need from a bridge ISP from site A that goes from ISP router to switch to AP bridged to site B with Station to switch. I now want another bridge from B to C and B to D. with site B and C on same network/security but D separate network. So A is one network, B and C same network and D a third. A is my home, B is my office in 1/4 mile away and C is a workshop is 1/4 mile North of B and D is a rental house is 1/4 mile south of B. So the each need own security to no allow renters or workers into other networks. What is correct way to setup these bridges?

 

Here is a rough drawing, excuse the crudeness of the symbols/design but this gives a basic idea of the setup. I had the ISP at site B injecting with site B to C and B to D using a router at B instead of a switch, but then I added Site A with a new ISP and to get B working I had to replace the Site B router with a switch which in turn caused APs from B>C and B>D to stop working. I expect it's a router issue that I need to put a router at B after the switch but looking for some direction instead of chasing my tail so to speak as I haven't done much work with bridges.