Can we restrict sending mail to O365 group mailbox to only group owners?

[Pawan_Satope]

We want only group owners should able to send email to respective O365 group mailbox. Other members of the group can only read the mails.

[#2]

If that's what you want, Groups are not the feature you should be using. Sure, you can restrict sending via PowerShell and the corresponding parameters:

AcceptMessagesOnlyFrom
AcceptMessagesOnlyFromDLMembers
AcceptMessagesOnlyFromSendersOrMembers
RejectMessagesFrom
RejectMessagesFromDLMembers
RejectMessagesFromSendersOrMembers

RequireSenderAuthenticationEnabled

However, even if you apply this to members, they can still create items via OWA or Outlook, and perform any other operations. 

[#3]

@Vasil Michev : Thanks for the reply. We have O365 groups where in some of the groups more than 100 members are there, hence we want to restrict it to only owners to send message to group mailbox. Also this groups are getting used in other communication sites and team sites as well for security and permission.

I will check the power shell command provided by you and let you know if any doubt.

[#4]

@Vasil Michev I check the powershell commands here for Set-UnifiedGroup . Is we have to individual email address in these command to accept message from owners. Is there setting where we can mention owners group and only they will able to send mail to group mailbox? 

[#5]

Nope.

[#6]

@Vasil Michev Thank you for reply. Also I have one more query, suppose i restrict the group mailbox by adding email address of owners, Is there way I can revert back in future to its original settings(i.e to allow all members to send mail to group mailbox)?

[#7]

You can just nullify the corresponding attributes.

[#8]

@Vasil Michevthanks for the explanation and workaround! what feature would you rather recommend to being able to restrict users to send emails to all members?