Helm has/merge option for overrides - kubernetes-helm

Question

I am trying to create a template whereby values have a default set of service names, unless they are overriden. example:
default:
service:
- name: nginx1
service: "dev-nginx1"
port: 8080
- name: nginx2
service: "dev-nginx2"
port: 8080
identifiers:
- identifier: "cust1"
- identifier: "cust2"
- identifier: "cust3"
overrides:
identifiers:
- identifier: "cust2"
service:
- name: nginx4
service: "cust2-nginx4"
port: 8080
- name: nginx12
service: "cust2-nginx12"
port: 8080
Where the above would yield:
---
identifier: cust1
service: dev-nginx
port: 8080
service: dev-nginx2
port: 8080
---
identifier: cust2
service: cust2-nginx4
port: 8080
service: cust2-nginx12
port: 8080
---
identifier: cust3
service: dev-nginx
port: 8080
service: dev-nginx2
port: 8080
I have tried the following, but i'm getting in a mess with the iterations in the incorrect place. Is there an easier way to accomplish this in helm with some sort of merge function?
{{- range $key, $values := $.Values.default.identifiers -}}
{{- range $overrideKey, $overrideValues := $.Values.overrides.identifiers -}}
{{ if eq $values.identifier $overrideValues.identifier }}
---
identifier: {{ $values.identifier }}
{{- range $value := $overrideValues.service }}
service: {{ $value.name }}
port: {{ $value.port }}
{{- end }}
{{ else }}
---
identifier: {{ $values.identifier }}
{{- range $value := $overrideValues.service }}
service: {{ $value.name }}
port: {{ $value.port }}
{{- end }}
{{- end }}
{{- end }}
{{- end }}