An assembly for a gas turbine engine, with a gearbox including a first portion having a first input gear coupled to a rotatable turbine shaft, a first output gear, and defining a first transmission path between the first input and output gears, and a second portion having a second input gear coupled to the turbine shaft, a second output gear, and defining a second transmission path between the second input and output gears different from the first transmission path. A fan rotor is coupled to the first output gear and a booster rotor is coupled to the second output gear on a same side of the gearbox than the coupling between the fan rotor and the first output gear. A method of assembling a drive for a fan rotor and a booster rotor in a gas turbine engine is also disclosed.