<form method="POST">
  <input type="hidden" name="parameter" value="a"/>
    ...
  <button type="submit">Submit</button>
</form>

public function handlePost(Request $request){
  $hiddenParameter = $request->input("parameter");

  if($hiddenParameter == "a"){
    // do something;
  } else if($hiddenParameter == "b"){
    // do something else;
  } else {
    // tampering prevention;
  }
}

<form method="POST" url="{{ url("/action/a") }}">
  ...
</form>

public function handleA(Request $request){
  // do whatever;
}

public function handleB(Request $request){
  // do whatever;
}

Route::post("/actions/a", "Controller@handleA");
Route::post("/actions/b", "Controller@handleB");