The only style that I have seen requires you to remove the front tire and the fork fits into a clamp style locking system. They actually modify a cleat to fit the clamp too.
If you don't want to remove the front tire, then I am sure you can build something out of wood/pipe/etc.... that bolts to the lower/rear track and you can use a quick tie-down strap to hold the rear of the bikes in place so they don't bounce.
If you don't want to remove the front tire, then I am sure you can build something out of wood/pipe/etc.... that bolts to the lower/rear track and you can use a quick tie-down strap to hold the rear of the bikes in place so they don't bounce.