How to deal with Security groups in SharePoint and Office 365 groups

Hi there,

SharePoint groups will continue to exist as SharePoint-only entities that can be utilized for permissions purposes.  You are correct that you cannot manage these in admin portal, and we have no plans to enable that.  

For group connected sites (including classic sites you connect to new Office 365 Groups), we do ensure that the 3 default SP groups exists (i.e. Owners, Members, Visitors).  While you will continue to be able to add your own SP groups to sites, any custom permissions you employ on site resources do not map across to Office 365 Group membership.  This is an important point - that while SharePoint will allow you to break permissions inheritance on resources, if you do so you can end up with members of the Office 365 Group *not* having access to those resources.

Hope this helps.

Tejas