Apache auth question

[Scott Sipe]

I am dealing with a company LAN that lives behind an OpenBSD based  
firewall+NAT machine. All internal machines have 10.x.x.x addresses.

One of the internal machines acts as an intranet webserver. Everyone  
in the building should be able to access it.

I would ALSO like to expose it to the outside, and have outside  
requests authenticate. So everyone with a 10.x.x.x still has no  
limits, and external addresses after authenticating with a username/ 
password have full access. Is this possible to do with apache2 config  
files?

Scott