Both at home and at office, I am part of a group of 4 to 6 where we all need to know one another's schedules. Not usually hour by hour unless certain events or activities deviate from usual daily/weekly pattern, but rather major events, deadlines, visitors, out of town trips, activities that will tie up parts of the work space, sub-group meetings, etc. Also, usually an aspect of the weekly pattern changes every 6 to 8 weeks, that is something that has been Mon at 4pm, may change to Thursday at 3:15.
At the beginning of month, we have been having a meeting in which each person in turn reads out loud his or her schedule and everyone writes down onto his own what is relevant. One person writes down everything and then puts this up on bulletin board. Then once a week we meet to share any updates and these get added in. also in same fashion.
Sometimes in such a meeting decisions are also made regarding dates and times for certain activities, supplies needed or responsibilities for them.
These calendar meetings takesforever and are really boring, and the exchange of dates is not fool proof either. We tried circulating a 6 person appointment calendar once a week but it was too hard to photocopy and you can't see wthe whole month at once. This did have an accountability advantage but it had to keep circuling through the group and then we would lose track of who had it.