You can use QHST to determine how many jobs are started in a subsystem.
But, I know of no why of determing what job queues they came from.
What would you do with this information?
Maybe there is another way to get it.
Check out the Job Notification Exit Point. You can, by subsystem, have the system send a data queue message to notify you whenever a job is placed on a job queue, when a job starts, and when a job ends. For jobs entering the system by way of a job queue the message includes the qualified job queue name. With this information you can, among many other things, count the number of jobs being run. The data queue message also includes a timestamp of when the job entered the system, when the job started running, and when the job ended.
Hope this helps,