Currently a linked list shows regardless of whether or not there is data available in that field currently. I suggest that unless the linked list has a parent chosen that populates that field, the linked list should be able to be hidden in the UI.

Example:
There are 2 lists. List 1, the parent, has 3 available variables: a, b, and c.
List 2 is the linked list and has data available to be chosen for variable c.
If nothing, a, or b are chosen in List 1, List 2 should not show in the UI. If c is chosen in List 1, then List 2 should be visible.