Nope, you'll have to move/rotate it by yourself.
In action function of ENTITY a, you could create ENTITY b as it's parent.
Then in while loop at the very end (after moving ENTITY a) you could check, if ENTITY b exists, and if it does, then move/rotate it with ENTITY a.
action move_test()
{
my.parent = ent_create(CUBE_MDL, my.x, NULL);
while(my)
{
// move my
if(my.parent)
{
vec_set(my.parent.x, my.x);
vec_set(my.parent.pan, my.pan);
}
wait(1);
}
}
