this is bound to happen, why dont you create a repeating control and place your text box and the template part in it.
Check out this post:
http://alecpojidaev.wordpress.com/2009/08/26/a-mutually-exclusive-check-box-in-a-repeating-section/
The second form (with categories) might fit your reqs.
It may not matter. I have found that I can specify the field I want when I upload it to SharePoint. That is what is most important. I will look into the repeating thing later.