[Xymon] monitor an RDP user

I need to monitor and make sure the user is always logged on, it's obviously windows. I am using the bbwin client still, it has the who.dll external builtin but you can't specify any parameters for it.

I am mainly looking for idea, I can manage a batch file or a powershell to pass it to, search current session, find the user and "green if it's loggedin" or "purple".

I need a little more help with linux however, so my question to you guys is:

should I instead do this on the xymon server? grep the existing "who" report maybe and then spit out a new report name "useron" or something like that? If that's possible, should I look at analysis.cfg or should I play with xmongrep ?

Thank you in advance.

Gab