There is no scanner on the market that can trunktrack MPT1327 (follow one conversation while ignoring all other traffic on the system). You can listen to the radio traffic from a MPT1327 system in conventional mode but you cannot pick which user to hear and which to ignore.
There are computer programs that will take the data that comes over the control channel and use that to tell the scanner when to tune to a specific frequency and when to go mute.
Trunkview works very well, I have used it for a 900MHz system and also for a network of 217 & 220 MHz sites. If you go to the Yahoo Group for Trunkview and read through old posts, you can learn what you need to.
chris