CSS M4A1 airsoft material overriding any CSS M4A1 model

I got a problem as the title says, basically i made a M4A1 skin that makes it look like an airsoft weapon, but if you for example have a CSS weapons pack installed then that same M4A1 will also have that material?

So my addon material also affects the CSS addon material.

Can this be fixed by simply changing the material name/ file location?

Yes, however, it will no longer work for any weapons if you change the path/name

Then how can it be fixed? What can i do so it wont replace the orignial M4A1 material but only my M4A1?