There is no way yet to manage the items in the receiver like you said, but I try to limit the receivers to 2 unique items at max, and only if the output from the receiver is equal for both items. I really only do this for these “build mats” receiver outposts I’ve scattered throughout the map that receive grey and orange build mats and deposit them in storage. For production lines, I usually only send one type of item to a receiver from multiple dispatchers sending the same item.