Currently, I would have to invite them all, wait till each user activates, then I would have to go to each group, go to settings, and then add them as members and then select what kind of permission they have. 

It would be considerably more simple to have an csv that has these types of headings:

First_Name | Last_Name       | email                         | Group       | Permission

first                  first last           first@email.com            group1      member

first                  first last           first@email.com            group2      moderator

second            second last       second@email.com      group2      member

etc.