The "official" rule is 2 tents and an awning, or 1 tent, 1 camper, and an awning.
However, especially in the partial hookup loops, as long as it fits on the site, set up what you need.
I have personally had 3 tents and two EZ-UP type tents set up on my site back on the 2000 loop. Not a problem.
If you do need to set up 3 tents I would recommend booking a partial site and requesting Loop 2000. That way you are guaranteed to have plenty of room to set up.