I think perhaps perllol might helpful. It seem the first two columns are your key, and you wish to concatentate lines with the same key. So iterating over all records, push the data columns of a line onto a list stored in a hash record whose key is the first two columns.

push @{$hash{"$line[0]_$line[1]"}, [@line[2..4]];
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I'm not belgian but I play one on TV.