Deny messages from the following Notes addresses to be sent to the Internet

HCL Domino Domino Forum
1

Can I enter a group into this field to prevent users from sending internet mail?

2

Subject: yes - groups can be used

Yes. You can use a group in this field to Deny these Notes users from sending to the internet. Their internet email address should also be included in DenyMailByRecipient if they are not supposed to receive inbound internet email either.