Real Newbie question

[System]

Hello All,
I know this is a very basic question i am asking. but can't help:(

See i have a domian a.com.

Is it possible to use the Nameserver Records of different servers i.e.

a.com  NS  ns1.aaa.com
a.com  NS  ns2.aaa.com
a.com  NS  ns3.bbb.com
a.com  NS  ns4.bbb.com

so if ns1.aaa.com and ns2.aaa.com fails will my domain be resolved with ns1.bbb.com ????

or is this possible???? what would be the solution for this?

Rgds,
Tina.