You have to pick which object you're referencing to.
You can do this by creating an event "System -> Pick", or "Object -> Pick", there are a lot of options on there (such as pick nearest to something, pick nth instance, pick by UID, etc).
That sounds good on paper but I can't find a practical way to implement it. For example, I have three object types, when you shoot them, a particle is created that moves with that object. How would I pair the particles, notice that if you shoot the objects too fast the particle will apply to the wrong instance.
Demo
Project File