Put a post in at
Scan New England and see if someone has a software file for that area. I don't have an up to date file for that area, sorry. If all else fails you can easily create a file yourself using Freescan software. It's free, and with the EZ Grab feature in it you can copy/paste from almost any website and create files to your liking.
The Middlesex County section in the Wiki at scannewengland is up to date for information, as is Zone 5 of the MA State Police, which is the zone you want for monitoring the SP. As always, you can become a premium subscriber here at radioreference and download directly from the database too.