Rendering 2-3 hours of footage in to 10-12 min parts

So for awhile ive been trying to find a way to render all my footage at one time but make it in to 10 or 12 min parts. What I'm doing now is selecting around 12 mins of footage, rendering, and then repeat with the next 12 mins of footage.

I was wondering if someone knows a way I can do this because coming back every 15 mins to render another part is rather annoying!

Please let me know if there is a way and if so please a lot of detail as I am not a "pro" with Vegas. If you need any other info let me know.

Info:
Sony Vegas 10
Windows 7