Excluding workstations from "Workstation/Server failed during last scan"

From what I can tell currently if you set a workstation's "Asset State" to disposed this excludes it from the "Workstation/Server failed during last scan" list. Currently when we are disposing of assets we keep them stored offsite until we get rid of them and created our own Asset State field for this. They can be there for a few months at a time and keep failing scans all this time until they actually get collected and we change them over to "Disposed". Is there a way I can set it so that my custom Asset State is excluded from the failed scan list?