Hi Ulrik, if it were me, I'd physically separate one-star and two-star images right before I transmit them:
1) Ingest, rate & caption all of your selects in "folder #1".
2) Using contact sheet filters, isolate the images that have a two-star rating.
3) CTRL-A (select those filtered images), CTRL-Y (copy) them to "folder #2". Make sure "Move photos (delete originals)" box is checked.
** At this point, your one-star selects are in folder #1, and your two-star selects are in folder #2. **
4) Reset folder #1 contact sheet filters to show the one-star images.
5) Upload the one-star images from folder #1.
6) Switch to your folder #2 contact sheet, and upload the two-star images from there.
This assumes that no images ever need to go to both clients.