I think that you can "manually creating validators"
http://laravel.com/docs/5.1/validation#other-validation-approaches
Basically in your method instead of use a a Request injection, use the rules directly in the method and call the $validator->fails() method for every set of rules.
Something like this:
public function store(Request $request){
$rulesFirstRequest = ['field1' => 'required', 'field2' => 'required'];
$rulesSecondRequest = ['field12' => 'required', 'field22' => 'required'];
$validator1 = Validator::make($request->all(), $rulesFirstRequest);
$validator2 = Validator::make($request->all(), $rulesSecondRequest);
if ($validator1->fails() && $validator2->fails()) {
//Do stuff and return with errors
}
// return with success
}
Hope it helps