+ my @rows = grep {
+ push @{ $found->{ $_->{key} } }, $_->{id};
+ $#{ $found->{ $_->{key} } } == 0; # take just first registration
+ } @{ $json->{rows} };
+
+ $json->{rows} = [ map {
+ $_->{distinct_ids} = $found->{ $_->{key} };
+ $_;
+ } @rows ];
+