At this time, we don't have an option to save guests to specific lists. However, you can bulk invite guests based on events you've hosted or attended! This allows you to continuously invite the same group of people.
To do this, click on the "Invite" screen, and then click the filter icon. You can filter by events you've hosted or attended. Within these events, you can "Select All" guests - this will allow you to easily re-invite all of your friends from a past movie night or work happy hour!