Hey, I'm still not sure what you're trying to accomplish.

You can allow users on your site (live site, not the management UI) to create a group using the Group registration web part. That will show a form where you fill in the group's properties and create it. The web part also incorporates an approval process so you can control what the users are creating.

There's an entire set of web parts for managing groups, so if you don't want users to edit groups (again, we're talking about the live site) don't use these on your site.

You can find some examples on these in the Community site guide.

If you want your users to create groups from within CMS Desk -> Tools -> Groups, that's a whole different story.

You create groups on the page /CMSModules/Groups/Tools/Group_New.aspx and there's a whole set of pages that allow you to manage the various components of a group.

If you want your users to only create groups, you need to edit the management pages in such a way that would deny access to users that you don't want to edit groups.

To do that, I would recommend you create a new permission for the Groups module, call it 'Create' and check it in the Group_New page's code and give it to users who you want to be able to create pages. Then you can use the already existing Manage permission to grant access to group editors.

To conclude - if you want to do this from the live site, then you don't need to change any web parts, or use any macros. If you want this to happen from the UI, you will need to adjust the code of some pages.