django rest framweork: combine ValidationError from multiple validation

Let's say I have the following serializers:

class AnswerSerializer(ModelSerializer):
    answer_text=CharField()

    def validate_answer_text(self, value):
        ...
        return value

    def validate(self, value):
        ...
        return value

class QuestionSerializer(ModelSerializer):
    question_text=CharField()
    answer=AnswerSerializer(many=True, read_only=False)

    def validate_question_text(self, value):
        ...
        return value

    def validate(self, value):
        ...
        return value

If validate_answer_text or validate in AnswerSerializer or validate_question_text in QuestionSerializer raise a ValidationError, the validate of QuestionSerializer won't be run. Thus, I cannot explain all the problem of the POST data.

Is there a way to run the validate function of a serializer even if one of it's field validator or children serializer validation failed and then combine all the errors ?

I have tried the following but did not succeed make it work properly. It does run both validate function and other validators but you cannot nest AllErrorSerializer and more importantly, it does not work when you do not have error: you can't save instance because you have inspect serializer.data.

EDIT

Due to Willem Van Onsem answer, I ended up with the following solution:

#serializers.py
class AnswerSerializer(ModelSerializer):
    answer_text=CharField()

    class Meta:
        model=Answer
        ...

    def validate_answer_text(self, value):
        ...
        return value

    def validate(self, value):
        ...
        return value

class QuestionSerializer(ModelSerializer):
    question_text=CharField()
    answer=AnswerSerializer(many=True, read_only=False)
    class Meta:
        model=Question
        ...

    def validate_question_text(self, value):
        ...
        return value

class BasicAnswerSerializer(ModelSerializer):
    answer_text=CharField()

    class Meta:
        model=Answer
        ...

class BusinessRuleValidator(ModelSerializer):
    question_text=CharField()
    answer=BasicAnswerSerializer(many=True, read_only=False)

    class Meta:
        model=Question
        ...

    def validate(self, value):
        ...
        return value

#views.py

class QuestionViewSet(ModelViewSet):
...
    def create(self, request):
        validator = BusinessRuleValidator(data=request.data)
        validator.is_valid()
        serializer = QuestionSerializer(data=request.data)
        serializer.is_valid()
        if (len(validator.errors) or len(serializer.errors)):
            return Response(merge(validators.errors, serializer.errors), status=404)
        serializer.create()
        return Response('created', status=201)