Record Manipulation Across 2 Files with AWK

[eldorado]

Hi there,

I would like to do a search across 2 files and concatenate matching line by using field 1 in both file as key.
If there is a duplicated key in file A, I want the matching line from file B to be concatenated to both the lines in file A.

Input File_A:

301|1234|NBS|
302|2000|ABS|
303|3600|ACC|
304|2800|ABS|
305|2880|ACC|
306|3100|ACC|
306|3200|BCC|
307|2030|NBS|
308|3600|NBS|


Input File_B:

301|AF_ACC_BDL|774;AF_WMG_BDL|6660;AF_REP_BDL|4735;
303|AF_ACC_BDL|1360;
304|AF_ACC_BDL|5092;
305|AF_ACC_BDL|32384;
306|AF_ACC_BDL|80859;AF_REP_BDL|80875;
308|AF_ACC_BDL|1418;AF_WLH_BDL|78273;AF_WSL_BDL|9990;AF_WFL_BDL|9998;

Expected output:

301|1234|NBS|AF_ACC_BDL|774;AF_WMG_BDL|6660;AF_REP_BDL|4735;
302|2000|ABS|
303|3600|ACC|AF_ACC_BDL|1360;
304|2800|ABS|AF_ACC_BDL|5092;
305|2880|ACC|AF_ACC_BDL|32384;
306|3100|ACC|AF_ACC_BDL|80859;AF_REP_BDL|80875;
306|3200|BCC|AF_ACC_BDL|80859;AF_REP_BDL|80875;
307|2030|NBS|
308|3600|NBS|AF_ACC_BDL|1418;AF_WLH_BDL|78273;AF_WSL_BDL|9990;AF_WFL_BDL|9998;

My code:

#!/bin/bash

awk -F"|" 'BEGIN {
while ((getline < "FILE_A") > 0)
   {a[$1] = $1 FS $2 FS $3 FS}
}
{
   FS = "|"
   if ($1 in a)
   {
      print(a[$1]substr($0, 5))
      delete a[$1]
   }
   else
      print $0
}
END {
   for (i in a)
   {
      print a
   }
}' FILE_B > OUTFILE

My current OUTFILE:

301|1234|NBS|AF_ACC_BDL|774;AF_WMG_BDL|6660;AF_REP_BDL|4735;
303|3600|ACC|AF_ACC_BDL|1360;
304|2800|ABS|AF_ACC_BDL|5092;
305|2880|ACC|AF_ACC_BDL|32384;
306|3200|BCC|AF_ACC_BDL|80859;AF_REP_BDL|80875;
308|3600|NBS|AF_ACC_BDL|1418;AF_WLH_BDL|78273;AF_WSL_BDL|9990;AF_WFL_BDL|9998;
302|2000|ABS|
307|2030|NBS|

Note that: 306|3100|ACC|AF_ACC_BDL|80859;AF_REP_BDL|80875;
has not been printed.


Any help in this is greatly appreciated. Many thanks.