Now, there is no possibility to share a calendar with team members and that all the members can edit that calendar. I think the solution can be calDAV. Then you can easily share calendars.
How come your sharing calendar has only 2 options and both options, the receiver/viewer can see all the details on my calendar. Don't you think you should protect your customer's privacy?
Please modify your calendar urgent. For now, you are offering ..take it or leave it..which is not right!