If you've surrounded them with pieces that do have the LinX, they'll hold the others in place just fine. It requires a bit of planning, but not too difficult.

The other option is to measure and cut your own LinX - more difficult, but certainly not out of the question.

Of course, there's no reason why you can't just lay the tiles against each other, without actually fixing them together! If nobody bumps the models too badly, they'll easily stay in place all by themselves. Alternatively, you can put a piece of felt cloth underneath, to keep the tiles from sliding.