Use a relay to make the items go into pneumatic tubes. Then I'm not entirely sure what you mean but if you need something to regulate it so one item goes one place and the rest go somewhere else create an intersection with a filter and an item detector, use the item detector to toggle a toggle latch connected to the filter to prevent items from going through. I'm not sure what you mean by the output being random but has a minimum of two, could you explain with more detail?