Are there any networking wizards around this afternoon?

There are about six different unsecured wireless networks in my apartment building. I have a Belkin wireless router that I use to provide access to my desktop via Cat 5 into the router - then I access the internet wirelessly with my notebook, a typical configuration. Is there a way for me to access one of the unsecured wireless networks on my desktop through the router, in the same way that I access these networks with my notebook, or do wireless routers (typically) only allow broadcast out?