[rules-users] top n - accumulate function parameters

I'm trying to average top N items. I can of course collect the items and do the rest in the consequence, but thought it might be a scenario applicable to a custom accumulate function. However, the accumulate function interface methods only take one parameter. If I were to declare a function top(N, things) within an accumulate call would drools autobox the parameters into some sort of collection? Maybe this is a naive solution anyway. I am still learning to think declaratively. cheers, -Jess