The answer is yes, and it's a practice widely used in the industry to distribute signals to multiple destinations without degrading the signal quality significantly. For a small fee (the procurement of the modules and the circulator) you can split/splice one physical fibre optic cable into multiple pairs. In the basement, there is the ONT+residental gateway device that converts the light impulses to Ethernet. However the real problem is how to create a balance, so assume room A is torrenting and taking up 90% of your internet bandwidth, then. We currently have two separate networks in our main building, and both need to be available and remain separate in the new building. Correct me if I'm wrong, but a fiber cable having 6 strands means it has 6 individual cores and they're independent from each other. You would still need to set up QoS (or 'Bandwidth Control') to achieve this, only you would have to set it up on both routers instead of just one.
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