Need Locks ( Any solution to my problem..)

Hi

I need locks for my small business ( 5 Locks) motel.

1. It is not in USA. But I can pickup in USA.
2. I need simple system.
3. There is a care taker for my motel, but I want to be able to control the room usage remotely.

Is there someway the locks has a mechanism which need the care taker call me everytime when he lets out the room for rent. I can set some time say day or two and the key code becomes invalid and he has to call me again.

My problem is we are away from the motel, cant be in the motel all the time. But I am looking for some solution which gives me more control.

Thanks