How to implement Outlook Express alike address field control

Question

Hi All, I was thinking about inserting some object (button, panel or static text) into textctrl, like Outlook Express does this.

You can see from a pic "group1" is an object, you can double click on it, when you delete it, it gets deleted the whole text not just a part of it. I made some research and this text field is just a simple RichEdit20W. I understand that I can do it by implementing some logic to a text field and so on, but it will not be proper way of doing it. I wonder how they done that. Should I implement IRichEditOleCallback interface to achieve that? I will appreciate your answer very much. Thanks!