Sorry, but what you're saying is not making sense to me.
output 1 file --> file 1 + file 2 where the third column of file 2 match with the four column of file 1
You show file1 records like this:
uuuuuuuu AAAAAAAA 001 A CCCCCC
"four column of file 1" is the 'A'?
You show file2 records like this:
uuuuuuuu A CCCCCC
"third column of file 2" is CCCCCC - do you mean second column of file 2 which would be 'A'? Or do you really mean third column and if so, do you mean the fifth column of file1?
If you're trying to match on the 'A' column, then why in output file1 do you show the u records that have an 'A' but not the 'x' records that have an 'A'?
Hopefully, you can see why I'm confused.
Are you trying to match on one field ('A') or two fields or what? If two fields, which two fields exactly?
You need to do a better job of explaining the "rules" using your example before I can help you.