If your pigs' cages are one cage with a grid division (each side is proper size for 1 pig), are they considered alone?
My two (brother) teen boars cannot live together now, but hopefully can go back to being together when they are mature.
They talk, sniff each other, growl and rumblestrut, wave their noses in the air and try to steal each other's food through the grids. Sometimes friends, sometimes challenging each other. When one is gone for awhile for floor time, the one left behind will start to wheek loudly and frantically, so they must be freinds?