In Office 365 Groups in Outlook, all conversations, replies to posts, and calendar events are delivered to the group inbox. But copies of them can also be delivered to the personal inboxes of group members. If you work primarily out of your personal inbox, having group items delivered there is convenient, particularly if you don't want to miss anything. But if you'd prefer to limit what goes to your personal inbox, you can do so by customizing the group email settings.
What are my group email options?
Group email settings are similar to inbox rules in that you specify where each type of group message gets copied to your personal inbox. The difference is that the group messages going to your personal inbox are copies of what goes to the group inbox. You can specify how to distribute conversations, events, replies, invitations, and calendar updates based on how you'd like to keep track of a group's conversations. This setting can be customized on a per-group basis. The following image explains each option.To customize how you receive group messages
In Outlook on the web (formerly Outlook Web App) select a group.
Select > Group email settings.
Select the desired option.
Repeat for each group.