Is it possible to attach 4 digital mics on a ADAU1781?

Hi there,

the ADAU1781 has two analog microphone inputs LMIC and RMIC which can also be used with two digital microphones, each. My question: Is it possible to use all 4 channels within the processor or am I limited to stereo on input MICD1 or MICD2? If so, is there another sigmaDSP-processor which can handle more than 2 inputs?