SO the main router has three separate fiber connections to each R1,R2,R3,
SO the main has three separate backup wifi connections to each R1,R3,R3
I have no clue what your network entails.......
yes
So a summary is that all four routers only need to provide automatic fallback between the fiber (primary) and wireless (backup) links.
Correct?
yes that is i need
And confirm what anav asked.