The groups which exist on Office365 will be regular email ids on SkyConnect which will have their mailbox pointing to Office365.E.g. if there is a group called on office365, then will be an email id on SkyConnect, whose location is Office365.Recommendation: While groups can contain mixed email ids from across both systems, it is advised that if a group contains a bulk of ids from O365, then the group be made on O365 and vice versa to reduce mail traffic between the two systems and optimize local delivery.