Does one of your integrateds have a preamp out? If so, you could use that to feed into the other preamp. You would lose some sonic quality on that leg of the circuit, but if you are dedicating it to woofers, you may not notice???
Using 2 integrateds to bi-amp?
Maybe this is a really dumb idea (if yes, please tell me why). Would it be possible to connect 2 integrated amps by Y connectors to a single source (e.g., TT or CDP)then use 1 to drive the L & R tweeters and the other to drive the L & R woofers of a 2 way speaker system? I have two integrated amps but don't have $ to go mono-blocks + pre-amp.