file.txt
23-Dec-07 12:34 A B C 
D E F G
23-Dec-07 12:35 A B C D E
F GG HH 

CODE:
awk -F\| '{ if ($1 ~ /[0-9][0-9]-[A-Z][A-Z][A-Z]-[0-9][0-9]/) { printf("\n") } printf("%s", $1); }' file.txt


output:
23-Dec-07 12:34 A B C D E F G
23-Dec-07 12:35 A B C D E F GG HH