hardstyler,
When I started writing this reply, I would've said no, but I dug a little further and I now believe it is possible.
The procedure is actually quite simple; create a sketch in your assembly, and inside your sketch, draw your pattern. Save the sketch. Use the Pattern Parts command, select the parts needing the pattern, and select the pattern.
Fun part in all this is that the properties of the pattern become variables of the assembly, simply link your variables to your excel spreadsheet and voilà! (I believe there are a couple threads about this... if you need more help, just say so)
Note: If using a square pattern, use the "fixed" mode, to have total control over length and occurrence.
hope this helps!
Martin