I don't know the talkgroup you're referring to. If it's not listed, then no one has submitted it to RR. Safe to say it's likely in the 208xx range, assuming it's a talkgroup. You could endeavor to discover it yourself.
How are you monitoring the Palmetto 800 system? With what receiver - scanner, SDR, pager? If a scanner, which model? Also, which site are you monitoring?
With scanners, you can set the receiver to play all active talkgroups on the site you're monitoring. With Unidens, it's called ID Search mode, with Whistlers, it's using a "wildcard" talkgroup. This could possibly reveal the talkgroup you're seeking, assuming it is indeed a talkgroup.
The talkgroup could be encrypted. I think by default Uniden scanners skip encrypted radio traffic, so you may find it difficult to track it down if it's encrypted. Whistlers don't skip over encrypted talkgroups.
Using control channel decoding software, like DSD+ or SDRTrunk or Pro96Com is another way to track down unknown talkgroups.
It's possible the channel is actually a conventional channel, likely simplex. It may not be on Palmetto 800 at all.
Hope this helps.
Brian