TXD replacement changing all known textures with same name?

[J.S.]

So I've made a script which was intended to change the texture of a single road. The code itself is fairly remedial and should come as no surprise

txd = engineLoadTXD("newroads1.txd") 
engineImportTXD(txd, 5506) 

The script successfully replaces the road which it was intended to replace, however for some reason it goes on to replace all roads using the same textures (dt_road and snpedtest1 to be specific) even though it was set to change only that single road (5506).

(Visual explanation)

Any clues as to why this is? Everything seems like it should be working as it should.

Edit: To clarify, the road I intended on changing is a single object, the others are separate objects.

[Chopper]

I dont think its possible, as txd has more than one texture in it.

[HunT]

It's possible with shader.

Create Object and shader function.

[hollow]

Still not fixed