That's a pretty cool macro janaya! Somebody was thinking.
Another way to check, but you wil still have to cross reference, is to go into LD 81, then list all phones with a feature of MWD. Probably not 100% accurate, but it would be a starting point and save some time.
If you have access to your voicemail system, you could also output a list of voicemail boxes and cross reference the other way.