styling a hover statement in SVG

I'm planning a web 'menu' based on this SVG illustation: the principle of my idea; a circle styled as being active, a circle styled as hover and an accompanying stroke that also needs to be styled

As I read the specs of an SVG file, I cant work with if-then statements.

I'm struggling with how to solve the hover styling of the stroke that is linking the two circles. In other words, how do I style an element in an SVG file when the element is

1. outside the trigger element

AND

2. based on the currently active page/active circle

I would appreciate help to find a way to do this - or alternative ways.

Thanks.