how to import and re-import a folder

I initially imported a folder /User/hp/abc/
into Devonthink’s group abc

The folder /User/hp/abc/ underwent daily update.
Many files got revised.
And some new files got generated.

I did another round of importing the folder
/User/hp/abc/
After the process, I noticed a new group being created in
abc — also named abc in which there contains
all the files in /User/hp/abc/

Is there a way to re-import /User/hp/abc/
into the same group abc
and without having duplications.

Thansk
HP

The best solution is probably to index the folder (File > Index…) instead of importing it.