If you would like to delete your items from one group, but leave them up in another, go to your Listings page, under the Manual tab.
Select and highlight the items you would like to remove. Scroll down and click Delete Facebook Photos for Selected if removing from a Facebook group, or click Remove Selected from Parties if removing from a Party.
You will then be able to select the group/album/or Party you would like to remove your items from.
There is a helpful tutorial video here: