> The current condition of httrack: I allready have a
> project contain 2 URL target and succesfully
> mirrored, then I need to add 1 new URL as target
> then I run httrack with update action,
> httrack will process all 3 URL.
> I want to do some modification so only new URL will
> be processed.

Add the third URL, and select "Continue an interrupted mirror". This should
reprocess quickly already downloaded links, without downloading additional
data, AND only download unknown link references.