The OP didn't specify, but I'm assuming that the traffic he's hearing is still on one or more of the Troop 7 dispatch talkgroups.
SCHP typically patches dispatch talkgroups together. This is done because they have fewer dispatchers than they have dispatch channels. I don't monitor Troop 7 often, but I think typically only one dispatcher is active at any given time.
Depending on which scanner you're using and how you have it set up, the result can be that you only see the "super group" of the patch as the active talkgroup. This means that if the Aiken dispatch talkgroup is the current "super group" in the patch, that's the talkgroup you'll see active, even if the Trooper's radio shows they're talking on the Orangeburg dispatch talkgroup.
On my scanners (GRE/Whistler brands), if I have all three dispatch talkgroups programmed and in my active scan list, I'll only see the active supergroup used, and it will show up as a typical "DG" transmission. If I lock out that talkgroup, I still will hear activity on one or both of the other dispatch talkgroups, but the display will show "ptch" indicating the talkgroup is part of a patch.
I have seen it happen that patches cross Troop boundaries. In my area, this means that occasionally a Troop 3 dispatch group will be patched with a Troop 4 dispatch group. I assume that each troop has their own dispatch center with their own dispatchers? I think that Troop 1 dispatch center is in Columbia, Troop 2 is in Greenwood, Troop 3 is in Greenville, Troop 4 is in Chester, Troop 5 is in Florence, Troop 6 is in Charleston and Troop 7 is in Aiken. But I'm not positive about that. Maybe someone else can verify? In Troop 7, even though the dispatcher may be physically located in Aiken, they might identify on the radio as Orangeburg when using that channel.