How to display the recipient's name in a chat?

Question

Django

I use django and drf

class Thread(models.Model):
    participants = models.ManyToManyField(User)
    last_message = models.DateTimeField(null=True, blank=True, db_index=True)
    is_chat = models.BooleanField('Чат', default=True)
    is_group = models.BooleanField('Группа', default=False)

    def get_last_message(self):
        try:
            return self.message_set.latest('id').text
        except:
            return ""


class Message(models.Model):
    text = models.TextField()
    sender = models.ForeignKey(User, on_delete=models.CASCADE)
    thread = models.ForeignKey(Thread, on_delete=models.CASCADE)
    datetime = models.DateTimeField(auto_now_add=True, db_index=True)

    def __str__(self):
        return self.text

Here is such a twist:

class Threads(APIView):
    permission_classes = (permissions.IsAuthenticated,)

    def get(self, request, format=None):
        queryset = User.objects.get(username=request.user).thread_set.all()
        serializer = ThreadSerializer(queryset, many=True)
        return Response(serializer.data)

And here's a serializer:

class ThreadSerializer(serializers.ModelSerializer):

    participants = UserWrap(many=True)
    class Meta:
        model = Thread
        fields = ('id','get_last_message', 'participants')

It turns out something like this api:

[
    {
        "id": 1,
        "get_last_message": "Hi",
        "participants": [
            {
                "id": 1,
                "username": "test",
                "pic": "/media/I45TU27WKS8U.png"
            },
            {
                "id": 2,
                "username": "Just",
                "pic": "/media/EUHT4ZC5ZE6R.png"
            }
        ]
    },

How to display only the recipient's data in participants? I thought through passing the second request using exclude (), but this is impossible.