I believe what you might want is one service mapped to two deployments, you could have two deployments with names bucket1 and bucket2 and have them labeled with one label app: buckets then have a service with a selector including that label.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: bucket1
  labels:
    app: buckets
spec:
  replicas: 3
  selector:
    matchLabels:
      app: buckets
  template:
    metadata:
      labels:
        app: buckets
    spec:
      containers:
      - name: bucket-container
        image: bucketimage
        ports:
        - containerPort: 80

apiVersion: apps/v1
kind: Deployment
metadata:
  name: bucket2
  labels:
    app: buckets
spec:
  replicas: 3
  selector:
    matchLabels:
      app: buckets
  template:
    metadata:
      labels:
        app: buckets
    spec:
      containers:
      - name: bucket-container
        image: bucketimage
        ports:
        - containerPort: 80

kind: Service
apiVersion: v1
metadata:
  name: s3
spec:
  selector:
    app: buckets
  ports:
  - protocol: TCP
    port: 80

But a further question would be why would you want to have that? if both bucket1 and bucket2 contain different information/data.

With Kubernetes generally, you would have one deployment with multiple pods/replicas to serve data either in bucket1 or bucket2 assuming the data is the same. If the data is different why not have 2 deployments with different DNS entries.

If you are using K8s 1.11 or later, you can also tweak the coredns ConfigMap in the kube-system namespace to possibly get what you are trying to get to but in terms of DNS you can't have a single record map to two CNAMEs as per RFC 1034, Section 3.6.2. You can't also hardcode IPs in Kubernetes since your IPs always change when your pods get created/removed.