List field with 'Select All' option? I have a Product content type with a list field of Groups (another content type). I would like to be able to have a 'Select All' item in the Groups list that allows the user to relate the product to all groups.

Note: This isn't the same as using javascript or ctrl+a to select all items in the list, because that approach would mean that when a new group is added it would not automatically be selected.
There are two workarounds that hit my mind, depending on the logic your UI could have.
1. If having no Group assigned could mean "assigned to all" - go for it.
2. Else: consider adding additional checkbox (boolean) field labeled "Fits all" (or whatever you like).