Offset entities direction?

is there a way to control which side the entity offsets to?

I have a bunch of grooves I need to offset one edge of...sometimesthe offset will go to the inside of the groove, and sometimes tothe outside of the groove...there doesn't seem to be any logic tohow or why it picks where it goes.

there's probably a hundred or more of these to do, but if i get ina rhythm, it's not so bad...but every now and then...it throws me acurve ballSolidworksSketching