You are assuming that they have the radars pack in close enough to provide that kind of overlap. From what I have seen that is simply not the case.
Do they need to be bunched together Spudman? To my thinking network latency would determine the maximum distance apart they could be and still offer some sort of interferometric support to one another. Pure guestimate of course but half the range to the target less processing time doesn't seem unreasonable so say 30 miles apart at 100 mile target range and more at greater range.
The other question is whether the rumours we've heard about aesa radars being able to spot stealthy aircraft are true. If so then it's likely it's because of something that aesas can do that legacy radars can't. To me that smacks of scanning regions of the sky in multiple frequencies simultaneously and picking up on the way that a stealth aircraft will reflect the different frequencies slightly differently. If that were the case (not saying that it is) could the same sort of thing be done with a PESA array as well? If they can then those Ruskies may not need L-Band systems at all and of course, the PAK-FA will field with an AESA.