In Civ V you can't have two military units on top of each other, but it's ok to have a military unit in the same hex as a worker or settler to guard them. The thing is, I have to move the settler and the military unit separately and make sure they end up on the same hex every turn. Is there a way to automatically group them together, so that I don't accidentally leave my settler or worker unguarded?
I have read all of the relevant sections of the CIV 5 manual in PDF form. I have experimented with every possible button in the user interface while military units are in the same hex as settlers/workers. There does not appear to be a way to automatically group the units together for defense. You have to do it manually, at least for now. Hopefully this will change with patches, or at least a mod.