IF Beethoven is the Alpha dog.
(sounds like a pecking order problem/
Jeolousy)

For the first bite it sounds like
Beethoven was letting Crunchy know
that I am top dog and I should be petted first. Which means you need to greet
Beethoven first, even putting your body
between Beethoven and Crunchy, till you
are done with the greeting.
Beethoven should move away when he
is done getting his greeting and allow
Crunchy to be petted.
If not, than upon greating Crunchy
if Beethoven growls or nips you can
give him a correction.
This is just one suggestion for this particular inncident.
Unfortunately there might be other incidents
as Beethoven is trying to inforce his
top position or possibly he is
challenging Crunchy for top position.