You may not want to delete any groups as we all know deleting contacts can be a daunting task. As we always suggest keeping your contact information segmented and organised will really help you to focus on the your sales and marketing pipeline. So if you don't want to delete the information, we suggest for you to organise and tidy them up using the archiving option in the system.
This doesn't remove the information from your account forever, it just hides the information.
If you wish to do this, all you have to do is go to Contacts and click on the Group Section
Find the relevant group that you wish to archive and simply click on the "Archive" button.
Click here to find out how to unarchive the information