Including of "edge particles" in the calculation

[Srdjan]

Hi,
I'll try to explain may problem on the photo below.
I'm calcualting density of vassels within the certain area. Therefore, I need not only the number but also area of each vassel. So, I know for the optioin "exclude particles" (like in the photo below), but does anybody know how to include the whole particle if the bigger part (center of gravity) of it is inside of my area, like in the case presented on the photo I attached.
Thank you in advance.
Regards.