INTERNATIONAL AMERICAN <HOME> SETS ACQUISITION International American Homes inc said it has contracted to acquire <Diversified Shelter Group Ltd> for about 11,850,000 dlrs to be paid 73 pct in cash and 27 pct in International American common stock to be valued on a 30 day trading average prior to closing. It said the price is based on Diversified's estimated 3.2 mln dlrs pro forma pre-tax earnings for 1986 after adjustment for certain non-continuing expenses. Diversified, a developer of single family housing in the Atlanta market, had 1986 revenues of about 25.3 mln dlrs. The acquisition if subject to International American arranging financing.