the way to do it is to only dress 7 or 8 guys for your games, set the player you want to play PG to be starter, backup, and scrub in the PG position, and tell your coach to strictly follow depth chart.
You aren't guaranteed of getting 48 minutes for each of them using your pattern. The first guy might play 36, 24, 0 minutes. The second guy 12, 24, 0 minutes. The last guy 0, 0, 48 minutes. Leaving the second guy with less than 48 minutes and less than full training. If none of them are heavy foulers, the way to do it is to only dress 7 or 8 guys for your games, set the player you want to play PG to be starter, backup, and scrub in the PG position, and tell your coach to strictly follow depth chart.