Question for some Guru's

[PrimalGraphixs]

I have been having this real creative Idea but had been tryingt o find an easy way to do it. Here it is:

Its a Female model shoot
Using an old roadway
Taking multip. shots of the same spot but with her posing in different spots on the road.

The question is how can i combine all three pose into one image is there a software that i can use that will automaticly do this for me or do i have to do the old fashion way and do some lassoing and blending in photoshop?

Heres is little quick ugly but quick digram so you can see what im talking about im a visual person my self usualy helps its and attachment please look.

Thxs