DB<117> %hash=()

  DB<118>  map { ($k,$e)=split '-'; push @{ $hash{$k} },$e } @CELLS 
 => (1, 2, 3, 4, 1, 2, 1, 2)

  DB<119> \%hash
 => { A => [1, 2, 3, 4], B => [5, 6], C => [7, 8] }