Personally, as long as the Haymaker isn't in the middle of the sequence, I would allow it.
Imagine...
A swordsman drives his sword with all his strength into the opponent, then swings twice to finish the job (Haymaker then 2 Strikes).
A swordsman slices at his opponents legs twice to immobilize him then drives his sword with all his might into the target's skull. (2 Strikes Then Haymaker)
Then again, it depends on dramatics, but I do think that this is possible.