Yes it is....
It's not ideal, but you could tweak the watermarking export to place them in a suitable subfolder already registered in Lightroom. So you wouldn't have to import them back in to LR as they would already be there ready to be made into a gallery. So it would be one extra mouse click.
An alternative is to re-think way you prepare and upload your images.
I used to create galleries on my PC and them upload them similar to what you are doing, but haven't done that for years. It's quick and easy to get the galleries in place, but it relies on your PC (and only your PC) doing the work and it's painful adding/removing images from an uploaded gallery (especially if your PC goes pop and you've lost the original).
The gallery I pointed you to is served by
Coppermine Photo Gallery; free server side software. There is no dependency on my computer and I can bulk upload new galleries which use the meta data to title and tag the images.
Another alternative is to pay for an image hosting environment which does exactly the same thing as Coppermine, with no setting up or maintenance hassles. There are lots of them around; my own website is hosted by SmugMug which has seamless integration with Lightroom; I pick the images in LR and they magically appear on my website - it doesn't get easier than that!