Hey @NC21 - great question. Thanks for your post! Firstly, check out our New User Guide - it’ll def prove helpful as you get used to the platform!

At this time there is no way to limit signups at all, to include by email address. You can include verbiage in your event description telling invitees that they are only to sign up for one time slot, however. You can also include this info in your confirmation email/calendar invitation (either/or), and a followup email that is fired off after signing up via Workflows, if you’d like!

I hope this helps! 

If there is a way to request this feature, pease do so!

Just added it to the list, @NC21!