If you are tracking a trunked system and you label the "radio ID's" you can turn volume up or down for each radio, it works a lot better on a P25 system as the analog radios don't release their ID as quick a P25 radio. If just listening to conventional system there is no way to separate one radio from another, exe. dispatch to unit one on conventional both volumes would change the same but P25 trunked if dispatch is lower (or higher) you can adjust it from each unit radio. Usually just the dispatch ID would need the volume off set adjusted on a trunked system.