programming - Return a Part by Reference? (For accessing hierarchical / structured data)

Is there a way to return a part of a list by reference, for reading and writing?

I want to do this so I can easily manipulate "rule-styled structured", i.e., hierarchical data that is loaded from a MAT file with struct's. Example:

obj = {"Name" -> "Something", "Age" -> 10};

I think this is a relatively simple way to get / set fields, which deals with nested structures by limiting Position to levelspec 1:

RuleQ[x_] := False;
RuleQ[rule_Rule] := True;
RuleQ[{}] := True; (* An empty list can be a Rule set... *)

RuleQ[rules_List] := SameQ[Head[First[rules]], Rule];

StructQ[x_] := False;
StructQ[rules_List?RuleQ] := True;

FindFirst[list_List, item_] := Module[{res},
   res = Flatten[Position[list, item, 1]];
   Return[If[Length[res] > 0, First[res], {}]];
   ];


FieldRule[field_] := field -> _;

GetFieldIndex[obj_?StructQ, field_] := FindFirst[obj, FieldRule[field]];

SetField[obj_?StructQ, field_, value_] := Module[{index},
   index = GetFieldIndex[obj, field];
   If[NumberQ[index],
    obj[[index, 2]] = value;
    ,
    AppendTo[obj, field -> value];

    ];
   ];
SetAttributes[SetField, HoldFirst];

GetField[obj_?StructQ, field_] := Module[{index},
   index = GetFieldIndex[obj, field];
   (* How to return a reference? *)
   Return[obj[[index, 2]]];
   ];
SetAttributes[GetField, HoldFirst];

So you can do something like

Print[GetField[obj, "Name"]];
SetField[obj, "Name", "REPLACED"];
Print[GetField[obj, "Name"]];

All that being said, I would like to do something like this:

GetField[obj, "Name"] = "REPLACED";

An example of my hope for such a feature:

GetFieldByReference[obj_?StructQ, field_] :=
    Return[Part[obj, {GetFieldIndex[obj, field], 2}];
SetAttributes[GetFieldByReference, HoldReturn];
obj = {"Name" -> "Something", "Age" -> 10};
GetFieldByReference[obj, "Name"] = "REPLACED";

The contents of obj would then be:

{"Name" -> "REPLACED", "Age" -> 10}