So it might get a little confusing, but here is my setup and my issue. I don't want to connect to the DECO made wifi connection. I have 2 buildings I need wifi in, The house, and a garage/shop that has a apartment built in. The shop is made with a metal roof, so it completely blocks any wifi signal or phone data connections. I contacted my ISP, and they installed a mesh system that consists of 2 externally mounted amplifiers that runs the wireless signal from outside the building, and the runs a ethernet cable to a rounter inside. This is also so my phone can still make phone calls from the 2nd building without having to worry about the metal roof.Issue is this box is rated for 2400sq/f and the shop is 4000sq/f. I don't want to connect to the deco wifi at all, I want it to be used as a wifi extender from inside the building, under my modems name. This is so I dont have to switch connections everytime I go from the house to the 2nd building/shop.

So long story short, It goes Modem(inside Building 1)<External amp(inbetween both buildings)<Router(inside building 2)<Deco(inside building 2)

Is this possible? Or do I need to just buy wifi extenders or figure another way out?