Exchange Online mail flow rule to filter domain sending to organization

You can try use this Mail Flow Rule:

On the Exchange Admin Center, go to mail flow, create New Rule. On the Apply this rule if, select Inside and/or Outside organization. Then on Do the following, choose Forward the message for approval to a person (admin@contoso.com). Add Exception on except if, select The sender's domain is and add contoso.com, fabricam.com, and microsoft.com