>>>I did not try to do anything underhanded and am shocked that there are some unwritten rules that I didn't know about.<<<

You should include basics such as whether adult or students, price per room, number of nights.

Many chain hotels (there are quite a few European chains, not just US ones) can provide what you need and most have a group booking link or phone number just like the airlines do for booking a group of 8 or more. Milan is a business city and used to these type of bookings for meetings, conventions, etc.

I agree with nochblad. OP is being unfair to the other posters in his/her last post. Can't she/he tell more about him/herself and about this tour?

There are really no "unwritten rules" but someone asking for an answer to a complex question really needs to set the scene. You didn't provide context so that people could help. Usually someone leading a large tour group has experience with bookings, etc. What's different here?

I hope no one was being difficult (we sometimes are) but the more information you provide, the better the advice will be.

One way to locate these types of hotels is to look at other tour companies and the group hotels they use.

Also, Milan has a very good subway system so you could stay a few stops away and be at the Duomo in a short amount of time.

http://www.atm.it/en/Pages/default.aspx

You STILL haven't explained the situation lots-of-fun. WHY can't you explain what you are trying to do?

You can receive 'much needed advice' but in order to receive it you have to GIVE enough information on which people can provide relevant responses.

You're like someone going to the dentist and saying, 'I've got a toothache', without saying which tooth is hurting.