Small Bge texturing prob...Help

There’s a problem with my texturing,
The buildings and all the other objects seem to have their materials and textures working when I press p but what’s the case if u find somethings have materials set to them and colours but still just come out blank white when p is pressed
Is it because those certain objects have multiple meshes joined as one but have different textures for different objects within those joined objects. If so how would I sort this out.
Please help I couldn’t figure it out all day.

just select the white faces and assign a UV texture/image to them?!

Right thanks