auto fill in with different contact lists

I have OL2k7.

My company has a "global" contact list with contacts for all employees. I
also have my personal contact list of family, friends and personal business
contacts. when i start a new mail, and in the To: field when i start typing
a name, it will auto fill an address. what i want is it for it to default to
my local contats first. i.e. i want 'Dad' to be an email to my father, not
"Dadson, John" (not a real name, but you get the point)

in my personal contacts my dad has his first/last name, but the display name
is "Dad" how do i get outlook to realize when i put "dad" in the To" field i
want my father and not a guy from a different office?

thanks