Just to reiterate, if you're trying to use two Vives in the same area, you just need a single pair of Base Stations. Any more than that and you'll have severe tracking issues. There's absolutely no reason you can't do it this way at all. If for some reason you, really, really, can't stand having two people with unobstructed LOS towards each other playing Vive using the same base stations, you'll need a partition that is thick enough to block IR and lasers, and then you can set two pairs up as long as they can't see each other at all. Thank you,
-John C