A couple of problems with your scenario of riding side by side...PWC's have to abide by the 150 ft rule....and the state requires any one over age 16 to have a boater ed certificate.
Can it be done? yes. Legally? No. Is it done? high likelihood
. Can there be a problem? Yes, if you are stopped for any reason by the Marine Patrol. Even a safety check, which they can do at any time.
Even when one is rented, the renter is required to have a cert. or take an exam and get a temp certificate. Good for one time. Hope this statement doesn't open up a whole new can of worms and take away from your post.
Short answer is that it can not be done legally. Sorry.
Again, welcome to the forum and enjoy your time at the lake and on the jetskis. Just take your friends for a ride with a licensed operator.