Setup: 9i

I call utl_smtp.rcpt multiple times to send to several users. The mail server sends the mail to each account just like advertised. The issue I have is that when I look at the value of the CC line in Outlook it is interpreted as a single address instead of multiple addresses therefore when you do a "reply all" the send will fail for everyone on the CC line. Has anyone seen this? I think this must be an Outlook thing, but I hope there is something that can be done to circumvent the issue.