How can I find out who is using our Transact object files?

We would like to have a way of finding out who is running our home grown
application.  There may be times when we wish to take the system down
so we need to know what is running to prioritize the timing.

We store our object code in a specific set of groups in one account.  We
have one file for each "program".  We use both compatibility mode and native
mode Transact.  This means we would need to know which files are in use.