Hard to explain easily without screenshots, but's here the technical answer in short if it helps:
create a dictionary with keys set to the UID of the objects its possible to click, and set the dictionarys values to 0. When you click an object, you can check if they have what you want thats required to click it (i.e. GET from dictionary where UID is a different object already clicked OR check a global variable OR something else) and if thats successful, set the key to 1.
Then the dictionary will be storing references for all the items that were clicked.