I doubt it. If you notice, the section mapping between the 601 and the 2500 is:
601 2500
2 1
3 2
1 3
4 4
The two top layer traces (section 3 on the 2500 to section 1 on the 601) could be routed on the bottom layer but they would have to go on the outside of the connectors and would be fairly long traces. The grounded pins on the pot sections for the 601 would also not correspond to a "channel".
Tell me more about your desire to have the separate ground planes, and what you feel constitutes a "channel".
My thoughts had been, as was done on Birgir's boards, to have the inputs on the right labeled as I1-I4 from bottom to top on the right side, and the outputs similarly on the left. I1/I2 would be a channel (+/-) and I3-I4 would be the other channel. As you can see above, if using the 601 pot, section 1 of the pot would be grounded on the L channel, but carrying the R+ signal (I3).