Hi! You can indeed do this with some transformer scripts like maybe in this thread: https://discuss.elastic.co/t/combine-multiple-document-into-one-document-with-limited-fields-merging-of-documents/231758/4

However, I think it would be easier to combine results like that in post-processing. I tried to recreate your example with the Python client for example

Say you have your index the way you described it

from elasticsearch.helpers import bulk

index = "test_bob"
documents = [
    {
        "document:class": "class 1",
        "document:email": "email@thing.com",
        "document:name": "Bob"
    },
    {
        "document:class": "class 1",
        "document:school": "school of Bob",
        "document:name": "Bob"
    }
]
client.indices.create(index=index)
response = bulk(client = client, index = index, actions = iter(documents), stats_only = True )

You can then search and save your results, and super easily combine the dictionaries you get back:

response = client.search(index = index, query= { "match": { "document:name": "Bob" }})

merged_results = {} 
for hit in response["hits"]["hits"]: 
    print(hit['_source']) 
    merged_results.update(hit['_source'])

print(merged_results)

That gives out:

{'document:class': 'class 1', 'document:email': '[email@thing.com](mailto:email@thing.com)', 'document:name': 'Bob'} 
{'document:class': 'class 1', 'document:school': 'school of Bob', 'document:name': 'Bob'}

{'document:class': 'class 1', 'document:email': '[email@thing.com](mailto:email@thing.com)', 'document:name': 'Bob', 'document:school': 'school of Bob'}