If I put X in "To: " then Y and Z in "Bcc: ", Y and Z will see that I sent the email to X, not to them. I want them to see that I sent the email to them (Y sees To: Y, and Z sees To: Z). Is is possible ?
What is your spec? Are you trying to spam people? Are you trying to avoid generating that much traffic so your mail server won't get blacklisted due to spam by sending the single message with all the recipient names?
If not, you can use any one of many different scripting languages (ie php, ColdFusion, ASP) to loop through a mail list or a query of e-mail addresses and send an individually packaged/wrapped e-mail message with only one "To: " to each recipient.