How to create group hit of notes?

Rereading OP and see it is only for a single clap sample. There are a bunch of free clap VSTi’s that will give you a bunch more variation than a single sample ever will. I’ve been using Clap Machine from 99Sounds for ages, but you should check out the KVR database to see what the current options are. I don’t generally use Groove Agent but assume it has a variety of clap sounds available.