It should theoretically be possible. What you might want to consider is making a subplate to sit on top of the original tabletop. Drill some dowel holes through the subplate and into the table with as much precision in spacing and diameter as you can muster. If you were to space the dowel holes at 6" centers, then you'd have the option of lifting the whole subplate (leaving the part undisturbed), move it along to the next dowel hole position (6" indexing), fasten it back down and continue machining it.
Now you would not do this within one program, because you'd need to reset the part datum after you move the part. The easiest way for the noob to do this, is to also reposition the part in your cadcam, bringing the farther reaches of the part nearer to the origin, so that when you create toolpaths, the XY numbers are within range of your table travels.