I believe InnoDB has row level locking, but MyIASM only has table level locking. So, looks liek you need InnoDB tables. I have never tried this so can't say for sure how it works.
That was what I was afraid of, cause that's what i thought, default MySQL tables only allow table-level lock. I knew InnoDB allowed both row and table level lock, I just didn't want to jump into InnoDB tables. Looks like I have no other choice!