I have an Office 365 Group in my tenant, and it is connected to SharePoint (https://mytenant.sharepoint.com/sites/mygroup). It is also connected to Microsoft Teams, and it has a private channel (connected to SharePoint at https://mytenant.sharepoint.com/sites/mygroup-myprivatechannel). I want the members of that private channel to have special permissions on the main SharePoint group site. However, if I just made another group on https://mytenant.sharepoint.com/sites/mygroup, it wouldn't sync whenever I added or removed a member from the private channel. If I make a security group in Azure Active Directory and update that, it won't sync to Teams. Can I just add the Members group of https://mytenant.sharepoint.com/sites/mygroup-myprivatechannel to https://mytenant.sharepoint.com/sites/mygroup? Or, is there a way to sync a security group as members of a private channel in Teams, or sync the members of a private channel in Teams to a security group in Azure Active Directory?
Quoting the official document:
Membership to the site collection owner and member groups are kept in sync with the membership of the private channel within Teams.
Any changes to the membership of Owner or Member groups in SharePoint Online will be reverted to private channel membership within four hours automatically.
So technically, you can sync a security group with the membership of the private channel by adding the security group to the Owner or Member groups of the SharePoint Online site created under the private channel.
The problem is that these are not real-time changes, so we will have to wait and see if this is actually effective.