Multiple Extensions forwarding to 1 voicemail box

I found a solution to this here:
http://forums.freepbx.org/support/documentation/howtos/how-to-make-multiple-extensions-use-a-common-voicemail-box

which I had already considered doing, however I was not sure if there was a ‘better way’ at this point.

I have about 100 extensions that are dynamic (added/removed/changed regularly) that all need to send any voicemail that comes into those extensions to a single voicemail box.

Any suggestions?

Thanks!