Zooming in on a group of elements

Keeping with my previous question about routes on a map...

Is there any straightforward way to dynamically zoom and pan such that
when a route is selected it fills the entire viewport?

I think that this question degenerates into determining the extents of a
group of drawing elements.  I've looked at the DOM interface for the <g>
element and it doesn't look like this is part of the specification.

The "objectBoundingBox" keyword looks promising, but I'm not sure exactly
how I would use it to affect the viewport.

Again, any suggestions would be apprciated.

Jason Foster