[Typo3] Allow only one content type in a column ?

[Tom Walter]

I asked already in a forum and a few days ago in the German list but did 
not get any answer yet. (Besides somebody mailing me if I got an answer ....

Seems to me that this is not possible (yet ?) with typo3 - but since it 
would be helpful to have here again:

Is it possible to allow in the backend for a certain column only one 
content-type (f.e. text or text w/picture) ?
I use an extension which should be only allowed in one column and in 
this column no other content-types should be allowed.

It would be even better (deluxe version) when after clicking new content 
in this column right away the form to enter data for this content type 
would apear (no need to choose since there is only one type available).
Is that possible ?

Tom