I would also question the need/want for a voice ID on P25, though if adjusted properly and unlike most voice IDs it may work well.
As for how, it greatly depends on your equipment. Often P25 repeaters are transparent where they receive the data, perform FEC, and rebroadcast. There are a few that have builtin interfaces but others require additional equipment. Quantars, for example, are transparent repeaters and require a DIU3000 to interface at a wireline level.