There are some books to look at (perhaps more than these):
Ritterman, M. (1983). Using hypnosis in family therapy. San Francisco: Jossey-Bass.
Kershaw, C. (1991). Dancing with dragons: Hypnosis in couples therapy. New York: Brunner Mazel.
Haley, J. (1985b). Conversations with Milton H. Erickson, M.D. (Vol. 2): Changing couples. New York: Norton.
Haley, J. (1985c). Conversations with Milton H. Erickson, M.D. (Vol. 3): Changing children and families. New York: Norton.
Lankton, S. & Lankton, C. (1986). Enchantment and intervention in family therapy: Training in erickson-ian approaches. New York: Brunner-/Mazel.
Lankton, S., Lankton, C., & Matthews, W. (1991). Ericksonian family therapy. In A. Gurman & D. Kniskern (Eds.), The handbook of family therapy, volume 2. New York: Brunner Mazel.
There will be good for starters.