From previous experience, any .pm dropped within Kernel/System/Ticket/Number/ is available for selection. 

Note that ticket number has, up until this request, been agnostic to what it points to, and so if you ever change the queue in which sits the ticket, you're going to have an interesting time reconciling the multiplicity of ticket numbers that might be assigned to a given ticket, or program in such a way that any ticket is automatically assigned all possible ticket numbers internally or ... 

Have fun.