Well, a very very simple way to display /who result to an @window would be to use raws.
The raw for the /who result is 352. The raw for the 'end of /who search' line is 315.
raw 352:*: window -a @WHO | aline @WHO $2-
raw 315:*: aline @WHO $2-
/aline is a little blocky, but it does it's job.
What did you mean by "Server Window"? /who will, by default, echo in your Status window. Simply change the "aline @WHO" in the code to "echo -a" if you wish it to show in the active window.
I suggest you do some reading too to help you understand, and customise, the above. I suggest
/help /window and
/help raw.
Have fun
Regards,