Question about Outlook Express

My wife sent an email to a distribution list she created using a Category she created in Contacts.  She sent it from her WLM account, but after sending it, it appeared in my WLM account's Sent folder, and it's evident the addressees got a message from my identity.  My account was the first WLM we set up and we added my wife's account recently.  Does my account act like a "parent" with respect to Contacts?  Is there any way for her to send to a Contact Category from her own account?  Thank you kindly.