Custom Radio Buttons Coding

Does anyone know the actionScript to apply to custom radio buttons? I want them to function exactly like the component radio buttons available in CS3, but I can’t use those because adding one makes the .swf about 30k and I have a 30k limit on all flash files.

I imagine the radio button would have to be a mC with frame 1 a drawing of a button unchecked and frame 2 the button checked. Then another mC of 4 of those radio button mC’s grouped together and coding to tell it that when one is clicked to unclick the others, but I haven’t been able to figure it out. I haven’t been able to find any info on this online since everyone just uses the component versions anymore. Any help is appreciated.