Maximum # of secondaries?

[Michael Cunningham]

Hiya folks,

I want to setup an extensive dns system for my company which has 
10 serperate internet links around the world and about 10 domains
as well around the world. 

Basically I hoping to achieve:

1 master and 10 slaves for our external dns around the world.
   and
1 master and 11 slaves for our internal dns around the world.
 
Is this doable with bind? Can a master have 11 slaves and still 
function properly? Will the internic deal with 1 master and 10 slaves when
it comes to external dns? I know I dont need so many external dns servers
but the boss wants redundancy for each internet link. The internal dns
servers will be forwarding their Internet lookups to the external dns
servers. 

Thanks.. Mike