load balancing - How to balance the root domain using NS records?

I have two load balancers that balance incoming traffic
across multiple data centers. These work fine. I can test them out by doing an
nslookup example.com
xIP

I have now taken out DNS
services with DYN.com to allow me to manage the DNS Zone file so that typing example.com
will ask my load balancers what the IP address is to
resolve.

Step 1 : the NS record for
www.

I set up A records (glue) for ns1 &
ns2, then the corresponding NS record to delegate the DNS lookup to the balancers
instead of DYN.com's
nameservers.

ns1.example.com A [ip
            address of load balancer 1]
ns2.example.com A [ip address of load balancer
            1]

www.example.com NS ns1.example.com
www.example.com NS
            ns2.example.com

All is
well - when I type www.example.com, the requests get delegated to my load balancers who
provide the IP address of the endpoint and the connection is made
successfully.

Step 2 : the NS record for
root.

This is where I run into problems. I need
customers to be able to type 'example.com' (without the www) and ALSO get delegated to
the load balancers for the IP
address.

However - of the research I
have done, and through the DYN control panel, it seems to be not allowed to provide an
NS record for the root - as this overrides the default NS servers.

How can i delegate both the root and the www.
to my load balancers?