Currently whenever I create objects in the repository, their default owner is my user account. I would like to change this so that the default owner will be the first group my user belongs to. How do I configure that? Or is this a customization?
That's customization (can be done in a TBO), however, this could be a security issue. Are you sure that ALL users in the group would have the same permissions on the documents ?
PS: Never did that so I also recommend that you check it is supported to use a group instead of a user as the owner of an object
Read my blog entry on the inherit permissions from for more details on other configuration options:
http://johnnygee.wordpress.com/2006/09/29/inherit-from-who/
