You'd have to time it perfectly so that you arrive to loading, or to the merge point, in the LL queue just when the others arrive from the standby queue. Of course there is no way to know with that precision how long each wait will be. Plus, even if you did manage to arrive exactly at the same time, it's probably unlikely that you would be seated together, since often the LL people and the standby people are loaded into different vehicles (though on some rides there is a merge and then everyone is loaded together).