At the few scales I have been to, there has not been enough width around the scale to be able to weigh only one side of the rig. But other people on this forum say they have done that.
As for individual axles, yes, you can stop so that the trailer axles are on different segments of the scale. You might end up with the back of the TV sharing a segment with the trailer front axle; then you'll have to do some math.
Keep in mind that when you have the WD bars hooked up, the weights change when the TV nose is tilted up or down. So if you stop with the TV front beyond the scale, it may be downhill, throwing your numbers off. I think the answer for that is to stop with the trailer's rear axle off the scale at the back, just barely not on the segment.