I hope this makes sense...
Are there any way that I can assign a person to add other users and assign them to shopper groups directly from the front end?
The person will have a data capturing role and must not be able to edit or access the back-end/core files.
There are loads of ACL options in VM ( which I have never played with) but feel free to... ;)
You may be able to assign a Joomla user group just to manage the VM users