M365 Exchange & Shared Mailbox Calendar Notifications

M365 Business Premium tenant here. 

We have a shared mailbox (not resource mailbox) called meetings@ The aim is to have an anonymous email address staff can send out meeting requests to our clients and have a dedicated calandar for those meetings. I've set up the staff members with Receive and SendAs permissions so everyone can set up meetings using that account so that the meeting invite appears to come from meetings@ instead of the staff members email address. Staff can create meetings and the invite is anonymous so that part is working as planned.

The problem is, all the staff gets flooded with Accept/Decline messages going to their personal mailboxes. Is there a way to set it so that only the shared mailbox gets the notifications or even supress those messages entirely.

I've resorted to email rules for each staff member to either block or divert the messages but I'd really prefer it if there was a one stop shop rahter than having to configure individual's mailboxes to block them.

I tried 

Set-CalendarProcessing -Identity "email address removed for privacy reasons" -RemoveForwardedMeetingNotifications $true -AutomateProcessing AutoUpdate

but it didn't seem to do much.

Any other ideas?