Design Pattern: Associated Items

I’m currently struggling with a rule. The rule needs to be triggered by any item in a specific group. So the trigger is similar as in your example.

However, in your example, the rule processes all items in that group. I would like my rule only to do stuff with the single item that was triggered.

So how do I identify the item (in group gDoors in your example) that triggered the rule?

Thanks,
Dries

[edit]
I may have found a solution, not sure if it is “best practice”, but initial tests seem to point out it is reliable.

when   
    Item gRaamcontact received update
then
	val LastWindowContact = gRaamcontact.members.sortBy[lastUpdate].last
	logInfo("Window","Last contact =" + LastWindowContact)
end

I’m not sure if it is always reliable when 2 contacts are changed at the same time…

[/edit]