For kti changing. Have a screen with a link to all teh kits and one that says drop current kit (if owned).
Have all teh kit links with restrictions, tehy all say that they must have NO KITS. Then the drop one has no restriction and doesn't lead anywhere, but can drop any kit. Now, when the kit is dropped, it will go to the page where they originally could pick it up, and the cycle completes.
It's your decision. MY advice, go for the longest possible.