Ok, than you are probably looking for the sticky bit, SUID.Here some links to...

Ok, than you are probably looking for the sticky bit, SUID.
Here some links to understand the meaning of it.

Background info:
http://www.codecoffee.com/tipsforlinux/articles/028.html

Brief example:
http://wiki.linuxquestions.org/wiki/Suid

Click Here!