Soon! In the near future HighSide will support a feature called, "guest users."
Guest users are people from outside of your team/organization who can be invited to join your HighSide team with limitations on which groups they can/cannot join. Guest users will have limited access and permissions.
An example use case for guest users is inviting a client of yours, a vendor, partner or friend, to participate in select groups within your HighSide organization.
Team administrators will be able to remove guest users access at anytime.