if the list of host is the result of a search, you can use a sub search
source="status.log" [search findmyhosts| dedup host | table host]
| replace up with 1 in status | replace down with 0 in status | timechart span=1m first(status) by host
or save the list of hosts in a lookup and call back the lookup in your subsearch.
Or if you want to do a form with the list of the host in a dropdown, read the dashboard editing options.
see http://docs.splunk.com/Documentation/Splunk/latest/Viz/Buildandeditforms
... View more