Shell Programming and Scripting

Hi Experts,
Please bear with me, i need help
I am learning AWk and stuck up in one issue.
First point : I want to sum up column value for column 7, 9, 11,13 and column15 if rows in column 5 are duplicates.No action to be taken for rows where value in column 5 is unique.
Second point : For duplicate rows, need to make them as single row in output file.
Third point : For duplicate rows, want to put all value of column 2 other from input file in column 16 in format (IN272018000235^IN27201523963) in output file other than value which is stored(IN27201800023963) in column 2 in output file.

Ex - In output file, please see column 16 it should have value as IN272018000235^IN27201523963(taken from column2) only from first three rows(duplicate) .Here we have not taken 3rd value(IN27201800023963) in column 16 of output file from column 2 of input file bcz we have already stored in column 2(IN27201800023963) of output file.

Have record of thousand of line..so duplicate rows are not limited to three, there can be 40, 50 any number of duplicate rows. So accordingly need to have value in column 57.

Please let me know if still my query is not clear

Input File

Code:

a|b|c|d|e|f|g|h|i|j|k|l|m|n|o|p
    POS|IN27201800023963|2018-04-24||27AACCE5198E1ZJ||500|0||9|45|9|45|||
    POS|IN272018000235|2018-04-24||27AACCE5198E1ZJ||500|0||9|45|9|45|||
    POS|IN27201523963|2018-04-24||27AACCE5198E1ZJ||500|0||9|45|9|45|||
    POS|IN27201800022938|2018-04-05||27AAJFH2012G1ZS||2|4||6||7|8|||

Expected Output File

Code:

   a|b|c|d|e|f|g|h|i|j|k|l|m|n|o|p
    POS|IN27201800023963|2018-04-24||27AACCE5198E1ZJ||1500|0||9|135|9|135|||IN272018000235^IN27201523963|
    POS|IN27201800022938|2018-04-05||27AAJFH2012G1ZS||2|4||6||7|8|||

Below is code tried to sum up value but giving output as

Code:

awk 'BEGIN{ FS = OFS = "|" }
       NR > 1{
           if ($5 == f5) {
               $7 += f7; $9 += f9; $11 += f11; $13 += f13;
               $15 += f15; $16 = $16 f2"^"$2
           } else { print rec }
       }
       {
           rec = $0; f5 = $5; f7 = $7; f9 = $9;
           f11 = $11; f13 = $13; f15 = $15; f2 = $2
       }
       END{ print rec }' input.txt

Code output: Not correct because getting column 2 value "IN27201523963" also in column 16 instead it should be like "IN272018000235^IN27201800023963"
The value which is present in column13 should not be present in column16.

Code:

POS|IN27201523963|2018-04-24||27AACCE5198E1ZJ||1500|0|0|9|135|9|135||0|IN272018000235^IN27201523963
POS|IN27201800022938|2018-04-05||27AAJFH2012G1ZS||2|4||6||7|8|||