Group Mode Edit Beachballing

I’ve got a project with all drums in a folder and I’ve calculated hit points, spliced at the hit points and quantised. The gaps between some beats are bigger than others. I don’t want to use Crossfade, as I’d like to do it myself.BUT…each time I close the gap…Nuendo beachballs for about 5-6 seconds on every edit. At this rate…I’ll be dead before the drumtracks are finished. Any ideas as to whether this is a project corruption or possibly a preference issue? OR pilot error( to which I don’t mind a bit of stick). I’ve left it in Group Edit mode, and taken it off. I am moving the folder start and end points.
It’s driving me insane with a 3 minute track taking anything up to 4 hours to edit.
Help? Anyone?

OK, Got it. If you remove Hitpoints after you’ve quantised the group edit, all is fantabbydozy. Thanks to a bit of research