Shell Programming and Scripting

awk     '!A[$2]++       {IX[++MAX]=$2}
                        {B[$2 FS $3]=B[$2 FS $3]","$1}
         END            {for (i=1; i<=MAX; i++) {T1= IX[i]
                                                 print T1 "(" A[T1] ")"
                                                 for (Y in B) if (Y ~ "^"T1)
                                                                {T2=B[Y]
                                                                 sub (T1" ", "", Y)
                                                                 sub (/^,/, "", T2)
                                                                 print Y"="T2}
                                                 print ""}
                        }
        ' file
FM(7)
AA=OA1,YT0,YT4
BB=KW3,ON7
CC=OA0,ON0

FN(5)
BB=FN1,OY1
CC=OY2,OY3,KW1

FT(2)
AA=OA3
BB=FN2

awk '  {
          A[$2]++
          B[$2 FS $3] = B[$2 FS $3] ? B[$2 FS $3] "," $1 : $1
          if(!tmp[$2 FS $3]++)order[++c]=$2 FS $3
       }

function orderp(subs,mains){
                             for(j in B){
                                        if(j==subs){
                                                    split(j,X)
                                                    if(X[1]==mains)
                                                    print X[2]"="B[j]
                                                   }           
                                        }
                           }

    END{  
               for(i in A){
                                   print i"("A[i]")"
                                   for(m=1;m<=c;m++){ orderp(order[m],i) }
                                   print ""
                          }
       }
   ' file

FM(7)
AA=OA1,YT0,YT4
CC=OA0,ON0
BB=KW3,ON7

FN(5)
BB=FN1,OY1
CC=OY2,OY3,KW1

FT(2)
BB=FN2
AA=OA3