Thanks for the request. Currently there is a way to set this property through powershell for groups, but it only works for users in OWA. We have this in our plans for Outlook desktop as well and will be working on it.
An error occurred while saving the commentKarin Y commented
This is a must have feature for our organization so that we can use Group Calendaring for company wide information dissemination about events at our organization.
Hi, As announced at Ignite Sep 2020, we will be making this functionality available as an open source tool by the end of the year. It can be used to pull in 1 or more security groups (nested or not) to drive the membership of a M365 Group. The membership will be pulled in as a flat list and kept in sync with the security group membership. However, if you have a pressing need for it before then, please reach out to GMMSupport@service.microsoft.com for a download of the tool. There is no support provided for the tool from Microsoft, other than answering any question around how we use it here. Link to the tool demo at Ignite: Making IT more efficient with improvements to Microsoft 365 Groups – https://aka.ms/Admin1011