server level exec permissions on specific function

Hello Everyone,
windows 2003 enterpr, sql 2005 sp2
we have 30 dbs, and every one of them have the same Scalar-valued Function.
Also, a windows auth login account that have to have a right to exec that function within every database
Question: i can make this function global by creating it in a master db or i can go to every single database and grant perm
to exec that function for this windows login.....
is there any other way to grant function exec permission for this specific user on the server level?
so it can be done once, and not for every single database that we have
thanks