I created three calendars in SP 2013.  One calendar is the main calendar and the other two is what appointments are being scheduled into.  The main calendar just displays the appointments.  I copied all fields the exact same way with the same information.  I used a "Copy Item" action after a value has been selected from one field to copy the item to the other calendar that the value was triggered off of.  Then it is set to delete the item from the other calendar to only have one value showing.

I get the following error: "The workflow could not copy the item. Make sure the source and destination lists have the same columns and column settings."