Hi,
That seems like it would be very helpful, especially if you could set the limit at the group level. Maybe to implement it you could include an optional priority setting for each job and/or a window of time within which the jobs in the group would run. When the limit on the number of running jobs within a group has been reached, the scheduler wouldn't start any more jobs within that group. When the number of running jobs for the group falls below the limit, the scheduler would start the next job with the group that hasn't yet been run during that window of time. Maybe a notification could be added that would alert an administrator that a job hadn't been run during the window of time for the group so that they could adjust the limit and/or window of time for the group.
Thanks!
Mike