Users are unable to select alarms for Maintenance Windows based on a specific Alarm attribute value when that attribute is not among the four default attributes provided in the filtering options.
There is a functional requirement to have all attributes, including custom attributes, available for selection within the Maintenance Windows configuration.
This functionality is currently not available in DX O2 SaaS.
An internal enhancement request has been opened to address this limitation and expand the available attributes for Maintenance Window alarm selection.