Sounds perfectly plausible. By Helping both sides, side N counter influences it's own effect, thereby, creating no change.
If side 2 is helped by the effect of side 1 both benefit in equal measure for the fight. Actually, the trick is, to remove side N. Then, something would actually happen.
I don't think side N is helping anyone. it is just neutral. If it joined one side then it would work against the other, but doing nothing is neither helping or working against them. It would be like i helped a kid who is beaten up by not beat him up too. Which would be wrong. Side N would have to join a side to help or do damage.
Is that a homework topic?
I suppose you could make this look like the Soviet Union / Russian involvement in the 2nd world war / cold war (er, I think)