Oh yes it can!! Believe it or not. My bf's ex-wife is collect child support payments from both the child bio-dad AND her ex-husband. I did some research on past judgements and yes, it happens!
If you are asking if 2 different people can pay child support on the same child...no, that would not be legal. The legal birth parent pays child support on the child. I am assuming that you are saying that one parent has custody of the child and the other birth parent is paying, as well as a 3rd party?? Why a 3rd adult would be involved is beyond me.
Yes. In 1992, Nebraska order five men to pay child support on the same child. The mother prevented a Paternity Test being done due to it being a violation of her privacy. In those days, three samples were required.