PROC SQL;
CREATE TABLE Test1 AS SELECT DISTINCT
ID,
AA,
CASE WHEN A_IND = 1 AND AA = 1 THEN  'A' END AS MODEL1,
CASE WHEN B_IND = 1 AND AA = 1 THEN  'B' END AS MODEL2,
CASE WHEN C_IND = 1 AND AA = 1 THEN  'C' END AS MODEL3,
CASE WHEN D_IND = 1 AND AA = 1 THEN  'D' END AS MODEL4
FROM Test;
quit;

DATA Test2;	
	SET Test1;
	COMBO=CATX(',', OF MODEL:);
	MOD_NUM=COUNT(COMBO,',')+1;
RUN;

PROC SQL;
	CREATE TABLE Test3 AS SELECT DISTINCT
	COMBO,
	MOD_NUM,
	COUNT(*) AS AA_COUNT
	FROM Test2
	WHERE (COMBO NE ' ' AND MOD_NUM GE 2)
	GROUP BY 1, 2
	ORDER BY 3 DESC;
QUIT;