Using multiple switching voltage regulators

I just did a search and didn't see anything on the subject. Forgive me if this has been covered.

Normally I'd take a 12vdc source and use a switching voltage regulator to step it down to 5vdc. With this regulator let's assume it has a 1 amp max draw on the 5vdc side. If I added a second switching voltage regulator and connected the 5vdc rails in parallel, would I have a theoretical 2 amp max draw? Would I need some diodes between the regulators and their parallel connection?

Could I do the same thing with the DC legs of a bridge rectifier? Would they need diodes between the rectifiers and their parallel connection?