Using Gallery 2 login to access Movable Type entries

Hi, I'm looking for a way to restrict access to my MT blog (i.e. - make it private). Is there any way I can use the Gallery 2 login/pass to grant users access to blog entries? I already have Gallery 2 installed and have about 40 people signed up there.

I thought about trying a Movable Type hack to protect my blog, but I don't want to inconvenience everyone by making them register again.

What do I do? Any suggestions would be extremely helpful.

thanks!