Open Source Tool for Managing Large Groups Available for Download


Organizations routinely use groups with a large number of members for executive communications, company townhalls, and other collaboration scenarios. Maintaining the membership roster of a large group is critical to ensure the right audience is included. Stale rosters have consequences - imagine how a team that was recently moved into an organization feels when they are excluded from their VP’s townhall because the townhall community member roster was not updated?


Group owners can spend countless hours, manually reconciling with spreadsheets or existing security groups to keeping the group membership accurate. It is much more efficient to have individuals maintain sub-group memberships (with <50 members) and automatically assemble the parent group roster as an aggregation of sub-groups.


We want to share with you an open source tool that makes it easier to manage a large group roster by taking advantage of existing security groups and/or smaller groups kept up to date by teams within the larger org. The tool takes security groups or other Microsoft 365 Groups as source group(s), produces an aggregated flat-list membership roster of the destination Microsoft 365 Group based on the source groups and continues to keep the destination group roster in sync with the source groups.


The solution is released "as is" under MIT license and Microsoft is not obligated to provide any support service. Deploying the tool requires experience in building, deploying, and managing Azure services. For more information on the capabilities and pre-requisites, and to download the tool, see Group-Membership-Management tool (


Please contact the Microsoft 365 Groups engineering team at if you have any questions, or would like to learn more about using the Group Membership Management tool in your organization.


-- The Microsoft 365 Groups Team

2 Replies
Hi Scott,
We are a company of 20 people working in Architecture and Interiors. We would like to further investigate the full potential of Groups and its ability to store and file emails from all people working on particular jobs. We use Office 365 and Teams prominently, but struggle to integrate outlook. If we are large enough to be useful I am happy to help and learn of what Groups could do for use. Thanks Vance