Calendar integration for booking process

As an agent, I always get tons of "block dates" from artists / bandmembers. Keeping track of all these, can be a bit annoying - especially when it's a lot of Bands, with a bunch of members, sending their block dates.

It would be cool, if some sort of calendar function could be implemented, that (mobile?!) users (= artists) gives the power to add "block dates" in "the group calendar" - so the agent sees, if a Band would be available for an event on a certain date, or not.
Maybe even extend this thing, and have the grouped calendar. Depending on given permissions / rights - Dates/Bookings could be handled in/out of Master Tour.
"Block" / "Pending" / "Confirmed" / "Cancelled"
Then the user would have an overview of what's going on.

Not every artists just does (longer) tours, but also one-offs or weekends only....
I believe this would help every user, no matter if "professional" or "mobile".