Help with a certain tricky problem

Ok first off I didn’t know rather this belonged in textures and materials or the modeling thread, I’ll allow a mod to decide where it should be posted. Now to my problem…

So I’m trying to make a RCT3 CS but I ran into a bit of problem. To import it I have to make sure that my Cube in this example with a simple texture is in a group. Basically heres one of the answers I received:

Correct, every face that shares a texture needs to be grouped together and the group assigned a name before it’s exported as an ASE file. Then each of those groups will show up in the Importer and you can assign the correct texture.

Tomsan’s method is one I’ve never used in all the years I’ve made custom scenery.

May well work for him, but it won’t for anything with multiple textures, nor any texture with any pattern that I can see.

So does anyone know how I can achieve this in Blender? If anyone knows how then it would be very much appreciated!