It works like three houses. There are paired endings for A ranks but which one you get is determined by their score unless you choose to only advance to A rank the one you want.
Olympia and Leda do have a paired ending but despite all the flirting in their support it’s all little on the vague side. Meanwhile Leda’s paired ending with Mu is unambiguously romantic. So big win for age gap onee-loli yuri I guess.