Start Transport In

Hi to all, thanks for the previous advices, and let me ask one more thing.

I’d like to transport products to one process point from more places at once.
It means I have four feeders and one process point. Once the first parts start “transfer” the others are waiting till the first is there.

I know there is “Start transport in” function, but if I put these function into process four times, and there only three last parts are on feeder, the last statement is still waiting…

Is there any way how to “count” parts and go further in process once the right amount of parts is transported?

Thank you for your advices.