Hair welds to another humanoid upon contact?

In a character creator in one of my games, the player chooses custom hair, and it works with a weld, with the Part0 to the handle of the hair accessory, and the Part1 to the character head. It works fine. The only problem, though, is when the character touches another NPC, for example a dummy made by the animation editor, the player loses the hair, and the custom hair goes onto the dummy. Can anyone help?