calculated item that count items on a host that are above a certain treshold.

[buijs]

I want to create a calculate item that count the amount of disks that are older than 5 years on a host.
I've tried it by using a calculated item, but I can not figure out how to set the threshold.
I can count the amount of disks by counting the item like this.
count(last_foreach(//smart.disk.hours[*]))
But that count the total amount of disks in the machine not just the old ones.
Any idea on how to achieve this?