%hash = ( subhash1 => { a=>1, b=>2 }, subhash2 => { c=>3, d=>4 } );;

sub getSubhash { 
    return $hash{ $_[0] } 
};;

pp getSubhash( 'subhash1' );;
{ a => 1, b => 2 }

pp getSubhash( 'subhash2' );;
{ c => 3, d => 4 }