Creating and Sharing a Secondary Calendar in Outlook with editing permissions:

Sharing a Secondary Calendar in Outlook with editing permissions is relatively simple, to do this click on File—New—Calendar

Give a Appropriate name to the second calendar and click on OK

Right click on the newly created calendar and click on Share “Calendar”…

Place a check mark in front of  “Recipient can add,edit, and delete Items in this calendar” and send it to the user that you want to share your Secondary calendar with.