During a hectic work week I have been known to leave my belt in my pants and put my pants on with the belt simultaneously. But is the belt consider another garment? And if so, would it be a violation of putting on two garments at once?
Seemingly being that in the Torah the avnet which was the sash or belt that the kohen would wear is called one of the BEGADIM
However at the same time I can tell u that since the only purpose of the belt is for the pants maybe they are considered one piece.