When our kids were younger several times we were told we would be at separate tables..never happened though.
As far as the DDE..when you sit down if you aren't all together, tell them you and the other table are all on one check.right up front..and it shouldn't be a problem at all.
My advice would be..try to have your group together and check in a bit earlier for your ps...you would probably have a better chance of being together. That is what we did anyway.