You obviously haven't towed a bike before.

Here are some of my experiences. It's amazing what you can do with a simply rack and electrical insulation tape...

The first picture shows my touring bike with the MTB attached. The front wheel of the MTB fitted neatly between the right pedal and the frame and was secured with insulation tape on the top tube.

The second picture shows how I secured the front fork with simply insulation tape. Four or five rounds of it in each location. The seat was taped across the top of the rack. I towed the MTB around 20km, including 2km on a rough gravel road.

The third picture shows a tandem, a fixie, a road bike and a frame or two on a trailer I built for various duties... it ended up moving my household stuff to storage. It did carry up to six MTBs for training courses at one stage.

The fourth picture is a close-up of the front fork drop-out clamp that I fabricated. It would be easier now to go to a bike shop and get the type for roof racks.

So, yes to the OP, it is entirely possible to tow bikes. For your purpose, a drop-out clamp bolted to the back of a reaer rack probably would be ok. The only problem you might experience is going over significant bumps (gutter crossings), but assuming you have lawyers lips on the bottom of the MTB's forks, you may be able to leave the quick release a little loose to compensate for this.