# Achieving split and sunk effect on a face without splitting the face

I created an object that looks like this:

As you can see the side of the bag is sunken in slightly and there are two triangular faces at the bottom.

I'm exporting this model out of Blender as an .obj and importing it into 3js. I've found that I've needed to modify the vertex textures manually in the .obj for each of the sides in order to map any images onto the sides correctly. Something like this:

The left is a representation of the outside sides of the bag and the right is the inside sides of the bag. But I'm having problems mapping the image onto the sides of the bag.

Because the sides of the bags are each made up of 4 faces the material maps the image 4 times, 1 onto each side, which isn't desirable as I just want the one image across the whole side.

Rather than splitting the side into 4 faces is there a way to achieve the same affect?

Here's the model.

EDIT