proportional resizing group of graphics

[viktoras didziulis]

is there any property that allows proportional resizing of grouped 
graphics when group's size changes. Or all one can do is setting width 
and height of each and every graphic within the group from within a script ?

Making a world map with countries represented by polygons. Now trying to 
figure out what is the best way to make it zoomable :-)

Best regards
Viktoras