Enable hobbit to alert about idle systems

Hello All,
I am searching for a way to enable hobbit to alert me if a host machine has not been in use by a user for a long period of time (eg, 2 weeks).

Example:
I have a system that is on loan to a testing group, the system is idle because they have not used it for 2 weeks.  Hobbit alerts me about the idle machine, so I can ask the users if they are done with it, and can take the machine back.

Thanks for any help,
-John B