Using ARR with NLB in 3 tier Architecture for High Availability

Hi,

I am creating an infrastructure for my software(s)

3 Web Applications

Web 1(Internet Application)-it has 2 web server and 2 application server

Web 2(Intranet Application)-it has 2 web server and 2 application server

Web 3(Intranet Application)-it has 2 web server and 2 application server

To achieve high availibility for all web server and application server ,

I am keeping 2 servers for each application at web tier and application tier.

I am Keeping a Network load balancer for the pair of Web servers for each websites at web tier and application tier.

My worry is NLB will be a single point of failure for each application.

Is there any way where i can use the combination of ARR and create a farm of NLB servers and make all 3 applications highly available.

Any suggestion or solution is highly appreciated.

Thanks in Advance