With different PL/DPL's there would not be interference on the repeater.... except for the fact that there is no repeater made that is set up for multiple tones. You would need multiple repeaters utilizing different tones. Take a look at Lincoln County, MS's EOC set up... One freq for output- 155.8950 MHz.... Two repeaters, one North, one South... each with the same inputs.... But different tones. And for large multi county districts for MS's Dept of Forestry, and Agriculture.... One freq for the repeaters... up to two repeaters per county in each district... a different tone on each repeater.
But for those agencies that can do the trunking route, thats the smartest route to go.