How do I query nested documents related by ObjectID with GraphQL - node.js

Question

USER has a field 'groups' which is an array of objectID's corresponding to GROUP
GROUP has a field 'boards' which is an array of objectID's corresponding to BOARD
BOARD has a field 'posts' which is an array of objectID's corresponding to POST
POST has a field 'comment' which is an array of objectID's corresponding to COMMENT
My goal here is to be able to query GrapQL like so:
Query{
user('_id'){
username
groups{
name
boards{
name
posts{
comment{
text
}
}
}
}
}
}
So by only supplying the query with the user's ID, I can get all the groups, boards, posts, and comments relative to the user.
My Type Defs are as follows:
type Query {
user(_id: String): User
groups(_id: String): [Group]
boards(_id: String): [Board]
posts(_id: String): [Post]
comments(_id: String): [Comment]
}
type User {
_id: String,
username: String,
email: String,
Groups: [Group]
}
type Group {
_id: String,
name: String,
bio: String,
owner: User
members: [User]
boards: [Board]
}
type Board {
_id: String,
name: String,
bio: String,
group: Group
posts: [Post]
}
type Post {
_id: String,
name: String,
board: Board,
comments: [Comment]
}
type Comment {
_id: String
text: String
}
schema {
query: Query
}
My resolvers (where I'm sure the problem lies):
const resolvers = {
Query: {
user: async (root, { _id }) => {
return prepare(await Users.findOne(ObjectId(_id)))
},
groups: async (root, { _id }) => {
return prepare(await Groups.findOne(ObjectId(_id)))
},
boards: async (root, { _id }) => {
return prepare(await Boards.findOne(ObjectId(_id)))
},
posts: async (root, { _id }) => {
return prepare(await Posts.findOne(ObjectId(_id)))
},
comments: async (root, { _id }) => {
return prepare(await Coments.findOne(ObjectId(_id)))
}
},
User: {
groups: async ({_id}) => {
return (await Groups.find({_id: _id}).toArray()).map(prepare)
}
}
}
Basically I'm trying to makle a big, beefy, nested query with a single call. All the models are related by objectID's. Does anyone have any input on how to proceed here or perhaps some links to related documentation? I've searched all over, but can't seem to find docs related to this specifically. Querying related documents by objectID.