Ernie- I think since both supplies are grounded wye's that you are required to have an EGC and the neutral brought to the transfer switch. The neutral will have to be switched by the transfer switch so you don't end up with redundant neutral bonding. As for the EGC - All of this equipment must be tied together via an EGC. I don't know what your Grounding Electrodes are or where they are in relation to your supplies but you will need a GEC running from the utility and the generator to the grounding electrode(s). I've got some engineer diagrams if I can find them I'll post them here. Drawn and published by IEEE.
