Nathan Fillion was in "Serenity" with Gina Torres.
Gina Torres was in "Matrix Reloaded" with Lawrence Fishburne.
Lawrence Fishburne was in "Mystic River" with Kevin Bacon.
Judi Dench... hrm.
Judi Dench was in "Goldeneye" with Sean Bean.
Sean Bean was in "Troy" with Brad Pitt.
Brad Pitt was in "Sleepers" with Kevin Bacon.
I'm sure there are other quality combinations, though.
Nearly every combination can be satisfied using: Sleepers, JFK, and A Few Good Men, which have the following notable stars:
Robert De Niro
Tommy Lee Jones
So on and so forth... that sort of star power represents about fifty years of prolific Hollywood work, thereby linking just about anybody to Bacon in a few steps. For a real challenge, eliminate those three films from consideration.
How about Elvis? Anyone?