Thank you for writing back and I am sorry for the late reply. I am from another country with a different time zone. Now, regarding this problem, you have two (2) good options to choose from.
First, I believe you have already created a distribution group. Your first option is to send an email adding "ANY" email address to the TO field, but you can also enter your OWN email address in the TO field and then, just enter the contact group or the distribution list name in the BCC field.
In this way, only the addressee (your email address) is seen on the TO field and the rest are BCCs. For instance, if you enter your own email address in the TO field and BCC the distribution list, when they open the email that they receive from you, the sender is you and it is sent to YOU but the receiver got a copy because of the BCC but the BCC addresses are not shown.
This is the closest way you can do it with Outlook and I am very sorry if your requirement is not met. That is how Outlook works.
If you really want to show the individual emails in the TO field when received by your recipient, but sent in batch, this cannot be done in Outlook 2013. I highly recommend using a third party mailer like MailChimp.
When you send bulk emails like sending to 50 emails at once and done in close time interval, it may be wrongly detected by the receivers' email server as a SPAM email. Or another way to put it, your email account can be tagged by other mail servers (the email servers of your contacts) as a spammer account because they detected a bulk mailing activity. This will end up with your emails being sent to their SPAM or BULK mail folder even though your email address is listed in their Address Book.
I highly recommend that you use a third party mailing service like MailChimp. Their email servers are technically configured for mass mailing and that your email account when used with this third party mailing service will not be tagged as a SPAM. This is basically intended for mass mailing like newsletters and this works exactly as your desired requirement: you send the email to a group of 50 and EACH will see only their email address in the TO field, no BCCs. And the good part, you can send to 2000 people at once, no groupings of 50 unless you really need to.
Another good part is that, MailChimp is FREE to use when you send 12,000 emails in one month and if you store not more than 2000 contacts. When you have more than 2000 contacts to send to, there is a minimal fee.
Please click on this link to start using MailChimp: http://mailchimp.com/
Regarding your Outlook, you can still use it to get their replies and just use MailChimp to send emails since it will be sending a bulk email without the harm of being tagged as SPAM.
I hope that helped.
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