2 drivers/2 families/1 rental car?

[disneyagain]

DH and I are going to California with another couple next spring and will be renting a car. Can both Husbands drive the rental car?? DH and I are both members of EA and would like to use that service...To add another driver to the rental will we need to stop at the counter???? If they join EA will that make a difference.

TIA!