[Koha] Problems with barcodes

Dear list, We have problems with barcodes. For the reason that we have two libraries and are going to have more (consortium), koha version 3.20.04 read barcodes when we imported records (using Stage MARC records for import) with the same numerals but different prefixes as the same barcode (as dublicate). for example two barcodes read as the same : FL0012345 and NL0012345 and Number of items ignored because of duplicate barcode. Your help is appreciated. Kind regards