Scheduling Overlap?

I scheduled two jobs. The both have a step that relies on the same
resource group called "Insert Prep Group". This group has finite
capacity and takes one scheduling block. It is checked to inform of
overload (even though this checkbox seems to do nothing for us- it
shows up either way on overload informer).

The job scheduling board is nice, as it allows us to see whats late,
etc of course. However.. I don't see on here a way to see if there is a
resource overlap. I can run overload informer - but what prompted this
whole thing is I scheduled two jobs and they both were scheduled and
now are using the same resource group at the same time. Seems Vantage
shouldn't have done this without alerting me when I scheduled or
looking at scheduling board, so there's probably another setting or
process I'm missing to catch this.
Any thoughts?