Can't copy alias into DT

I have a group in DT3 into which I want to place an alias to an OmniOutline outline. When I drag the alias into DT, it turns into the actual document, not the alias. (Under the Kind column it says OmniOutline document, not Alias.)

This means that if I make changes in the outline outside of DT, those changes are not reflected inside DT.

Is there any way I can import an alias into DT and have it always open the latest version of the document stored outside DT?

See File / Index Files and Folders

And no, aliases cannot be imported nor indexed.
Indexing an alias will index the original file.