Make Accessories multi-wearable tutoral?

[Gastalt]

I'm was confused in trying to find the tutoral to make accessores multi-layerable in finding lot of mesh tutorals, but confused on where the part the code to convert to multi-layerable was.    I have some maxis goggles recolors I want to mix with some custom gasmasks i found.  Since I can't alter the gasmask, the maxis goggles all i can change, so I'm trying to find the tutoral to make them multi-wearable.  If you can help, LMK, thanks in advance.

[Theraven]

Here
It might be easier to do it on the gas mask, though.

In case you need it, "How to make accessories wearable at all times"

[Gastalt]

Thanks, It's been driving me nuts trying to find it.