Conditions for a RollOut on a movie Clip

I have a movie clip (mc1) which when rolled over, another movie clip (mc2) fades in (sort of like a drop down menu). When you roll off of mc1, mc2 fades away. However, I would like mc2 to stay visible if the mouse is over it. I only want mc2 to fade away if the mouse is rolled out of both of mc1 and mc2 not only mc1.

Hope this makes sense, please help, thanks.