Feature: Having the same item in different groups

[TheArturthur]

Is your feature request related to a problem? Please describe.
Currently, if I want the same item in, for example, a public wishlist (registry group) and a group with other users, I have to duplicate the item. This could lead to errors if someone claims an item in the public list, as it will not be reflected in the other groups.

Describe the solution you'd like
An option selection in the item to add it to the groups it should belong to.
When claiming an item, it should be reflected in all groups.
The owner should be able to edit the groups the item appears in after creation.

Describe alternatives you've considered
It could have an "all" option, so that when the user is added to new groups (or new groups are created), the item is shown in those new groups automatically.