Variable hittests

i have a load of script that summons a bullet

function shoot() {
mc = _root.attachMovie(“bullet”, “bullet”+_root.bullet, _root.bullet++);
mc._x = ship._x;
mc._y = ship._y;

so i have summoned the bullet.

now i have an enemy

function spawnEnemy() {
enemy = _root.attachMovie(“enemy”, “enemy”+_root.bullet, _root.bullet++);

as you no bullet has been renamed to bullet+number

i now need to have an enemy hittest that checks to see if it has hit the bullet.

how can i do that.