Counting cells - complicated case

[Artsi]

Hi
I need to count numerus images of osteoclasts in culture sinve I have hundreds of them I want to do it with as much automation as possible. I tried to figure how to do it but havent had much succsess. This is the original image:
Each purple shape is an osteoclast and i'd like to have their area, perimeter and number.
I tried to use the color threshold and gi this:
but I don't know how to go on.
If I try the watershed it divides the into too many parts. If I try to analyse particles as is it counts them as a single thing.
Please Help
Hanna