As an admin user it would be fine to have an option to assign the users for the bulk operation with just one click.

At the moment we need choose all of the users one-by-one which is very time consuming (for eg. by 150 users) if I would like to modify for all of the users something with bulk operation

Idea:
to have an option to add the users to groups (then need to choose the proper users only once!) and then if it needs to modify sg with bulk operation then we have to assign the proper group and then do the "bulk operation"!