Just execute
hint ((("zgm_obj_1_c1_dyn" select [0, count _marker - 4]) splitString "c") joinString "area_")
No crash when executing long version:
_marker = "zgm_obj_1_c1_dyn";
_marker = _marker select [0, count _marker - 4];
_marker = _marker splitString "c";
_marker = _marker joinString "area_";
hint _marker;