Is the object an Editable Polygon object? If so, just select the subobject elements you're working on (polys, edges, verts), and use the "Hide Unselected" option in the Editable Polygon object properties, under the Edit Geometry rollout, to hide the rest. Or, vice-versa. You can also select an object, and Isolate Selection, withe the quad menu options, to work only on that object in a special isolation mode. Even in Isolation Mode, you can still hide selected or unselected polygons or subobjects, to further clip your work to only a certain area of interest.
