Sent Mail and POP Accounts

Sent Mail and POP Accounts

Given:

1.  I have a single user on my account and a primary email address associated with that user.
2.  The primary email address is hosted at zoho.com
3.  I POP email from several external addresses into Zoho mail.
4.  I also POP email from my primary account on zoho.com to my iPhone
5.  I POP email from my additional external addresses to my iPhone.

Problem:

When ever I reply to or send an email from my primary email address, using the online interface, they system automatically POPs a copy of the SENT message to my iPhone.  It is as though my address is listed as a BCC on the outgoing mail.  This only happens on my primary account and not for any of the other external accounts also POP'd to the iPhone.

Question:
Is there any way to stop the sent items from Zoho showing up on my iPhone?

Thanks!