TLV320ADC3101: How to do the AGND and DGND in a system with 3 TLV320ADC3101 on the same PCB

Hi, I've made a board before with one TLV320ADC3101 and had the codec in a AGND island with a net tie between the pad at AGND and DGND. It worked really well and I had no noise issues. I've read in Henry Ott's book that you should have a single ground plane for all AGND and DGND when you have multiple ADC converters on the one PCB is this the case with the TLV320ADC3101? Do I just change my schematic to have all GND instead of DGND and AGND and have a solid ground plane for GND. All the analogue stuff is on one side of the PCB and all the power supplies are linear LP5907 in the "digital" half of the PCB. There is some digital I/O coming in to the ADC from the top of the PCB and the analogue stuff is below that. That's easy to do because the pin out on the ADC encourages that. It'll be a 4 layer PCB. Let me know if there is an app note that discusses this config with multiple ADCs on the one PCB. In short is it ok to have one ground plane or do I have an island ground plane for the ADCs. If an island ground plane how should I attach it to the dgnd?

Thanks, Mark