Perhaps Len will check in on this topic, as he has done in the past.<img src=icon_smile_question.gif border=0 align=middle>
I'm no technician, and I used to think that it couldn't be done.<img src=icon_smile_sad.gif border=0 align=middle>
I really think it depends (like most things) on the bow, the arrows, the shooter, the broadheads, etc.
Right now, I have 3 different brands of ICS carbons that are supposed to be the same spine. Carbon Express 300's, Blackhawk Vapor 4000's, and Quick Strike 59's. The bow was originally tuned for the Carbon Express, and it will shoot field points and broadheads into a nice neat group out to 30-40 yards. The QS's shoot close to this with broadheads, just not as tight a group. The Blackhawks group decently (except for two of them) but the broadheads impact 3-5" left of the field points which group with the CE's. I think if I tuned the bow for the Blackhawks, this could be improved upon, but I'm not inclined to find out since the CE's group better anyway. There are a lot of variables to control, but I think it can be done most of the time, since I, who have limited experience, can seem get fp and bh to group together on most bows I've had in the last 5-6 years.
Avoid the inevitable until it is absolutely unavoidable!