Sending a signal to a process started by another user

[Joonas Paalasmaa]

How can I send a signal to a process started by another user. In this 
case my intention is to send a signal 14 to a process started by user jp 
from a cgi script. The script raises an "Operation not permitted"- 
OSError perhaps because the script is run by user "apache" and the 
process by user "jp". How can In make this work properly?

- Joonas