Newbie needs help with Events

Hello,
This is my first post on this forum, so please forgive me if this question has been previously asked.

I was wondering how to get an event to load based off the completion of other events. For example, I have three objects, each with their own event if you click on them. I want a seventh event to load only after each object has been clicked at least once, ie have my plot progress after the first six events. Does anyone know how to do this?