Shell Programming and Scripting

Please consider the following file, I have many groups which can be of 3 types, T1 (Serial_Number 1) T2 (Serial_Number 2) and T1*T2 (all other Serial_Number).

I want to only consider groups that have both T1 and T2 present and their values are different from each other. In the example file, Group3 and Group 5 are not to be considered for the same reasons.
Important to mention that the data is not sorted, so T1, T2 and T1*T2 rows are scattered in the file, in no particular order.

Code:

Group	Type	Value	Serial_number
Group1	T1	aa	1
Group1	T2	tt	2
Group1	T1*T2	at	3
Group1	T1*T2	tt	4
Group2	T1	gg	1
Group2	T2	tt	2
Group2	T1*T2	gg	3
Group2	T1*T2	tt	4
Group2	T1*T2	gt	5
Group3	T1	gg	1
Group3	T2	gg	2
Group3	T1*T2	gg	3
Group3	T1*T2	gg	5
Group4	T1	gg	1
Group4	T2	tt	2
Group4	T1*T2	gt	4
Group4	T1*T2	gg	5
Group5	T1	gg	1
Group5	T1*T2	gt	5

I want to add a column to the output , only for types T1*T2 that states if they match the corrsponding value of T1 in the group, or T2 in the group or doesnt match any of T1 or T2.


For example for Group1, the value of T1*T2 (Serial_number 3) is 'at' which
doesnt match its T1 value of 'aa' or T2 value of 'tt'. So it is 'different'

For Group1, the value of T1*T2 (Serial_number 4) is 'tt' which matches T2 value of 'tt' , so it assigned 'T2-like'

Code:

Group	Type	Value	Serial_number	Similar_To
Group1	T1*T2	at	3	different
Group1	T1*T2	tt	4	T2-like
Group2	T1*T2	gg	3	T1-like
Group2	T1*T2	tt	4	T2-like
Group2	T1*T2	gt	5	different
Group4	T1*T2	gt	4	different
Group4	T1*T2	gg	5	T1-like

This is my feeble attempt, which doesn't work.

Code:

awk 
' {
   if(!($1 in grp)) {
      grp[$1]++
      type[$1]=$2
      val[$1,1]=$3 FS $4
      next
   }
  NR != 1 {
 grp[$1]++
 type[$2]++
 val[$3]++
 a[$1,$2]=a[$1,$2]" "$3
 
 if($3=="T1") categ="T1-like"
 else if ($3=="P2") categ="T2-like"
 else categ="different"
 
 if($3="T1*T2")
   for (i=1;i<length(grp);i++)
   	if (grp[i]==grp[i-1])
   		catg1[i]=categ
   print $1 FS $2 FS $3 FS $4 FS catg1[i]
 
 }' infile