ssh ext issue.

I have an ext test that runs daily. Since I  not allows to install clients I ssh over get what I need test and report on the results. 


The problem is that when servers come offline I get false Positive. 


Is there a way I can leverage xmonnnet to test for ssh connectivity before I run the ext or as part of the ext  (ping is blocked ).  


How can I use xymonnet-again to run yellow tests again sooner ?


Thanks