Filesystem thresholds based on Space (not percentage) available

Trying to create a DA that alerts when filesystem has x GB left rather than percentage left.

This is valuable as setting current thresholds to 99% could still mean there is 100's GB still available, which for big filesystems this is not an issue.

This information is available through the host resource oid's and I have created a threshold which is visible on the devices the DA is aligned to. However, this is a threshold for ALL filesystems rather than being able to specify for individual filesystems.

Anyone with any ideas on how to get the same behavior as the internal filesystem thresholds where we can specify this threshold on individual filesystems?