Is there a way to adjust the calendar on all of my multiple listings at once?

[Clare0]

@Julz-and-Greg0 I don't think so since each listing has it's own calendar.  

[Lisa7]

I'm not sure if this is what you're looking for, but have you tried the multi-calendar option? I didn't discover it existed until I had been a host for six months. 

Here's where you find it. Your Listings --> View multi-calendar

I find it helpful to juggle listings. It's not a quick and dirty way to, for example, block off an entire month for all of your listings. But I hope this is what you're looking for.