L.featureGroup([marker_1, marker_2, marker_3]).addTo(mymap);
L.featureGroup([marker_1, marker_2, marker_3]).remove();
L.featureGroup([marker_1, marker_2, marker_3]).remove(mymap);
// Добавляем маркеры на карту
var feature = L.featureGroup([marker_1, marker_2, marker_3]).addTo(mymap);
$(document).on('click', '.delete', function(e){
feature.remove();
return false;
});