Mac takes a long time logging in

I'm new to Mac so forgive me if I say something wrong.

Basically I have a MacBook Pro which logs in fine when I'm at work but when I'm on my home network it takes like 5 minutes to authenticate. All appearances are that it's trying to reach my work network to authenticate. Short of disabling wireless or having it prompt for my home network password before joining wireless, is there any way that I can either shorten the timeout or have it bypass network authentication when I'm at home?

Thanks in advance!

 

Tested:

Tested: If not connected to my network (removed from airport connections) it logs in just as fast as when I'm at work.