A family of Microsoft word processing software products for creating web, email, and print documents.
Hello Greg,
Welcome to Microsoft Community and thank you for posting your query.
Let me assist you with Word issue.
You may use the real time co-authoring feature available in Office Web Apps and check if it helps.
If you want to do coauthoring using Word 2013, you need use SharePoint.
For more information about the same you may post in SharePoint forum.
http://social.msdn.microsoft.com/Forums/en/category/sharepoint/
I hope the above information helps. Let us know if you need further assistance.
Thank you.