[nsp] IOS NAT rotary-pool + overload

[rpcbind at speakeasy.net]

I'd like to be able to cycle through a nat pool to try and get some diversity 
(getting bad luck on per-flow load equal-cost multipath on provider side). 
I've got a rotary-pool configured presently, however it seems that when used 
w/ an 'overload' mapping, only the first address in the pool is used.

The rotary-pool is small enough that I must overload. Anyone know how to coax 
ios cycling through the pool before I setup several single-address pools and 
spread out across them using multiple access-lists and rewrite rules?