I browsed around looking for this feature and the closest I found was VarAC Frequency Scheduler.
I'm imagining using a local FM repeater for exchanging VarAC Vmails and bulletins, but only doing so in the early morning hours such as between 00:00 and 05:00 when the repeater isn't in use by voice users. (And, yes, I will be doing this with the knowledge of the group that owns the repeater).
Does the VarAC Frequency Scheduler accommodate this usage? To be clear, I don't want VarAC to attempt to send messages at any time except the acceptable window of 00:00 - 05:00.