Right Click on your Calendar on the left hand side of your Outlook Application
Click New Calendar
Name it according to the company name you prefer
Right click on the new calendar you just created and click share
Pick the people in the office you would like to share the calendar with
Now all of the people on that list will be able to view and edit that calendar from their Outlook Applications
If you want to be able to see these shared calendars on your mobile devices you will need to download the OWA app from the AppStore.