I'm confused with what you are asking, Can you post your model?
I feel your pain.
The bad news is this functionality does not really exist. The good news is there are workarounds.
If your offset entities are lines and arcs, you can add new parallel and/or concentric constraints to new edges (and tangents and dimensions as needed) to get the effect of an offset. Tedious, but it works.
If splines are involved, it's not so simple. Usually, if I'm offseting splines (or spline-like edges), I create construction sketches first so I can better control the source of my offsets. Takes a bit of experience and planning to know to do this.