ical syncing for 2 iphone pals?

Trying to assist my friends in setting up iCal syncing between their iphones and their iMac.

I have my Mac's iCal syncing wirelessly via icloud to my iPad2 and iphone.

I set up a "caldav" acct. for them in ical preferences using: p06-caldav.icloud.com as the server address.

Then each of them set up icloud accts. using the SAME email address and turned on calendar sharing. Now, one of then can SEE all the ical entries, and make changes edits.
The other can NO LONGER see the iCloud calendar option when she attempts to enter a NEW ical event/entry on her phone. Should she attempt to delete the acct. and then re-install it?

Thanks for the assist.

The easiest way to do this is logging into iCloud from a computer and in the calendar section you'll see a little signal symbol next to each calendar. You can then broadcast that calendar via iCloud to who ever you want and even allow them to edit the calendar. iCloud will send the user an email, the user opens it on their phone and then the new calendar will appear in their calendar app.