PHP shell_exec

Hi I have been using the shell_exec command to perform several server queries quite succesfully i.e. analysing files systems by gettin ginformation returned by df -kP (shell_exec('df -kP')). do any of you guts know if it is possible to target a command like this on another server? So from server A where I am running a web app, needs to run the shell_exec('df -kP') on server B, which also has php installed, so that i can display the results in my web app on server A. Hope that makes sense! Also, how would i fopen a file such as /proc/cpuinfo on Server B from Server A. Any help greatly appreciated Regards Ade