Audio Systems: small office, lobby, hall, 4 exam rooms, altec lansing, sound distribution

Question
I read your response to a couple of questions dealing with small office sound distribution including in-ceiling speakers and two rooms.  You noted the option of mono.  What additional equipment would be necessary for a lobby, hall, and four exam rooms in mono?  Except for the exam rooms, the spaces are different sizes.  What equipment would allow for adjusting volume in three areas or zones without buying three receivers?  I have had limited luck with a rather old multi-speaker control box on my home audio.  Thanks VERY much.

Answer
No doubt that I would have an opinion concerning sound distribution anywhere, since I have 30 plus years experience in the field, only I think you may have me mistaken for someone else since I do not recall commenting on this subject. I would have offered a very simple solution by recommending an Ethernet based system made by Comstar (a division of Altec Lansing). I suggest you look into it since I know of nothing that will give you the kind of flexibility you are looking for.