It isn't possible to list multiple email addresses as the Sender Email Address in Luminate Online. This field will only allow a single email address. Sending an email that appears to be from multiple people is not possible in most Email Service Providers and email clients. This is because it is a DMARC violation and easily recognizable as email spoofing which is well-known to be malicious. If you would like multiple email addresses to receive replies to an email message, then talk to your IT department about creating an email alias which essentially forwards emails that are sent to a single address, to multiple addresses.