You should be able to achieve that by using multiple streams. you will then use each metric as you wish. See this community post for an example (you won’t need to join the streams if you want just to write a message)
the message can be built in this way using the aliases
|alert()
.id( {...} ) // The alert title
.message('{{.Level}} - Disk Space > Total Disk Space: ' + string('Total_Disk_Space') + '| Occupied Space: ' + string('Disk_Space') + {...})
Some time ago I found this post which has a really nice and complete TICK script example, it might be useful as an example.
let me know if this works
Edit: removed a non-working solution