They should know each other.
On 20February2012, Bang and Zelo were a guest in Sukira . Actually, in this entry i want to say that ZELO NEEDS TO KNOW EACH OTHER WITH DONGHAE. This entry will explain you why i said that, click here. I hope that Donghae also know about this.
Down here i put their conversation. The conversation credit to this tumblr.
Zelo: My parents moved all the way here to Seoul because of me. They've been through a lot... Mom and dad I love you.
Ryeowook: Where are you originally from?
Zelo: I'm from Mokpo.
Sungmin: Donghae's hometown!
Ryeowook: Donghae hyung will like you a lot. If you see him later and tell him "Hyung~ I'm from Mokpo! Please buy me a meal!" then he will.
ALMOST! I Think they should know. T.T Kbai!