Sharing with public upload but without delete of existing files

I switched from an old OC 7 installation to latest NC and I love it!

I miss a feature for sharing for example photos:

On a vaccation me and my friends took pictures, now I want to share my pictures with them by using a link. I want them to have a rights to append files, upload their pictures, see mine and download them. But the active edditing feature allows them to delete my pictures as well. The only upload-checkbox hides my pictures from them. So there is no compromise.

Setting up accounts for each of them is a little too much …

So is there a solution, maybe with file permission addon?

Thx in advance for your support, I apprecciate it :wink: