never heard the rule
the confessor is the natural spiritual director for many people, and in general it is most helpful in the long run to find one good priest for confession and go to him every time. On the other hand, the confessional is not the best place for spiritual direction beyond that dealing with sin, temptation etc. Nor are all priests gifted or well prepared to offer direction to someone entering the latter stages of spiritual growth. Probably depends on what the individual needs in the way of spiritual direction.
