how to ignore "unknown" results in a trigger

[steev]

I have a bunch of servers. Those servers may or may not have some filesystems named /mnt/data1, /mnt/data2. etc.

I'd like to monitor the free space on these filesystems. I can make a trigger for this in my template but the problem is that the trigger alerts on the filesystems that don't exist and shows them as unknown.

is there any way to ignore an unknown status on a trigger or to only trigger if the item that the trigger uses actually exists?

[steev]

to clarify...

I was hoping to just have the template contain all the possible checks that I might need but then to ignore the rest. I'd like to do this so that I don't have to remember to manually enable/disable the triggers.