I think you need to work more on making everything in your collage's appear to be in the same environment. It's a little too apparent that the ladies are sort of "asted" on to the background. You see, the background has a lot of grain, and not quite as much contrast as the figures. Maybe you could blend them easier with adding some grain to them...lowering the quality of them to the quality of the background. Also the shadows are too defined. Also they do not seem to be pointing the same way. Maybe pay more attention to .... hmm... the porch on the building. See how the shadow on the porch lies against the building? It's sort of to the right...like the light source is to the left. So the shadows of the women would be pointing towards the right and not the left. And if the figures themselves have a light source that contrasts that of the background, then you could flip them horizontally so that the light sources match in both the people and the background.
Just ideas on how to make this look like one solid image, rather than many put together. I know you're a collage artist...but it seems that this was meant to look like one image.
It's very nice. I like the concept and everything.