curl -X POST 'https://api.example.com/memberships/batch' \
  -H 'Authorization: Bearer YOUR_TOKEN' \
  -H 'Content-Type: application/json' \
  -d '[
    {
      "id": "membership_jane_eng",
      "subjectId": "subject_jane",
      "scopeId": "scope_engineering"
    },
    {
      "id": "membership_agent_eng",
      "subjectId": "subject_agent",
      "scopeId": "scope_engineering"
    }
  ]'

[
  {
    "id": "membership_jane_eng",
    "subjectId": "subject_jane",
    "scopeId": "scope_engineering"
  },
  {
    "id": "membership_agent_eng",
    "subjectId": "subject_agent",
    "scopeId": "scope_engineering"
  }
]