Confusion about Groups and Groupings

Hi. In my course, assignment 1 is posted for different groups on different dates. So Group A does the assignment in Week four; Group B Week five, etc.

S|o I have to set up separate groups. How can I do this in one easy step because now I have to set up Groups, then I have to set up the same groups with the same student participants in Groupings.

Is there a way to set up a group in one step rather than two or three? Thanks.

Moodle 2.3