G Suite - Settings to allow external user to email a group

[TwistedHelixis]

Currently have the groups in the school so that only internal domain users can email to a school group.

 

The school is now part of a federation, and the staff at other schools would like to be able to email my school using the internal domain groups.

 

If I select edit and the public I get the following,

 

I only want external users to be able to email the group and that is it. I don't want them to be able to view emails that might have been sent internally by the group members, if that makes sense.

 

Is the last image OK for what I need?

[jthompson]

I think you might need External ticked for Publish posts.

 

I'd advise setting up a dummy group and testing it.