If you have your calender is on outlook.companyname.com, you should be able to Publish the calender to anyone you wish to share with.
In your calendar, on the Home tab, in the Share group,
click Publish Online, and then click Publish to Office.com.
You can also set who can view this calender along with other settings.
Outlook products are being merged (renamed :P) into Office.com so the sources I have below should relate to this.
Share an Outlook calendar with other people
Publish and share calendars on Office.com