router - Specifying which external IP addresses can access port 80

UPDATE 1:

I am using Apache 2 as the webserver. Can I block access to all IP addresses except 3 from Apache?

ORIGINAL QUESTION:

I have a Linksys BEFSR41 router and have opened port 80 for development purposes. Is it possible to block access to port 80 to everyone except certain IP addresses? So port 80 should only be accessable to about 3 ip addresses from outside the internal network.

I have tried looking at the manaul for the BEFSR41, but can't seem to find what I am looking for. Or maybe, I don't understand what this type of filtering is called.