[Marshall]

I would like a way to say have 5 reserved chaannels such that

from 12:00 - 3:00 we have
Channel 1: Sport 1
Channel 2: Sport 2
Channel 3: Sport 3
Channel 4: Sport 4
Channel 5: Sport 5

Nothing has to show on the EPG beyond 3:00, We don't know for sure the events that are to air.
Then at 3:00 or perhaps earlier the bacgroud library update occurs, and sees that the live events in the plugin have changed. So we use the same channels but now they will play something else.
from 3:00 - 6:00
Channel1: Sport 6
Channel2: Sport 7
Channel3: Sport 8
Channel4: can be blank? or duplicate?
Channel5: "" ""

I haven't seen any precedent of this anywhere

This is not possible with PTVL. You switch between live channels by switching channels, you don't mix live channels together into a single channel.