Discounts based on Joomla groups

I notice the sales page for Event Booking has the following listed as one of the features:
"Members discount: Offer discount if registrants are members on your site (members from different Joomla user groups can have different discount amounts)."
How do we achieve different discounts based on registrant's Joomla groups? I cannot see how that would be achieved at the moment?

See eventbookingdoc.joomservices.com/basic-s...nt#discount-settings (You can choose the groups, then enter Discount Amounts for each group (comma separated)

Tuan