What site are you monitoring? They may not be heard on many sites.
GHTD has 6 groups. I had them as 1-6 but the letters make sense as there are radios aliased "GHTD Dispatch A". So the channels might be GHTD A, B, C, D, E, & F
Groups (with the CPS-P3 dialing scheme TGID in parentheses.)
GHTD A=6691473 (500-88-900)
GHTD B=6691474 (500-88-901)
GHTD C=6691475 (500-88-902)
GHTD D=6691476 (500-88-903)
GHTD E=6691477 (500-88-904)
GHTD F=6691478 (500-88-905)