Limited but very recent experience...
Does anyone have any info about a group called GROUPWISE ?

This is suppose to be a timeshare resale group. Thanks
GroupWise is actually a PostCard Company, apparently based in Pennsylvania.
A family member recently purchased a decent week on eBay, at relatively low cost. The seller was identified on eBay as "octimeshares", or something close to that, but when the sale / closing paperwork arrived later, the real seller name turned out to be GroupWise, Inc., which had Power of Attorney for a couple who apparently relinquished the week to GroupWise (after
paying GroupWise who-knows-how-much to do so).
Closing was handled by Timeshare Title, also located in a nearby town in Pennsylvania (presumably there is a close relationship between GroupWise and Timeshare Title, perhaps even the same people own both). Closing costs were reasonable and competitive (I believe Bro' told me around $300). Bro' received his recorded deed and a copy of the resort notification just last week. The eBay auction occured in late June or early July.
In short, while this is certainly only a single isolated example, it is also real and current and one which has gone smoothly (albeit not very quickly). Younger bro' is quite happy with his acquisition; he knows the resort (he owns other weeks there already). He claims that similar weeks are "listed" (but not likely often sold) in the on-site resale office of that same facility for 7-8 times as much money as he paid in that eBay auction.
That's the total of what I know about GroupWise and its' associated closing entity called Timeshare Title.