How to get an end device switch between two different networks, i.e. two different coordinators

Hi,

I have two separate ZigBee networks, let's call them Z1 and Z2.

Z1 is formed by coordinator C1 on pan P1. C1 has two end devices attached to it, E1 and E2.

Z2 is formed by C2 on pan P2. C2 has no end devices attached to it. Below is a diagram representing the situation.

C1----------------------E1, E2          <- Network Z1 on pan P1, channel 14

C2----------------------(no end devices) <- Network Z2 on pan P2, channel 15

I want to change the setup into the following:

C1---------------------------E1  <- Network Z1 on pan P1

C2---------------------------E2  <- Network Z2 on pan P2

What is the best way to do this transfer of E2 from C1 to C2? C1 and C2 both exist in the same proximity. E1 and E2 are programmed with chanlist = 14, 15 so that they can latch onto the PAN with either channel. 

Everything in the network works just fine, except that I have not been able to figure out how to make E2 move onto the network created by C2. NLME_DirectJoin() will not work in this case, right? Because C1 and C2 are different networks. If C2 had been a router connected to C1 then it might have worked, am I right?

But my requirement clearly is to have both C1 and C2 as coordinators and I need to achieve this 'migration' somehow. Any help, pointers would be greatly appreciated. I am using ZStack 2.5.0 on the CC2530.

Thanks,
-- S