You can not add the tags(keywords) during the group creation process without custom development. However, once the group is created you can add a wiki application and a wiki page with a list of your associated keywords for that group. If you are looking to enable those tags (keywords) for search.
If your list is small, you could take advantage of the description field in the group creation process but it may have a character limit problem.
If you have any further questions or if you are interested in a custom group creation widget (Note: we have done something similar for another client) please don't hesitate to reach out.
