Rest API Search filter on HumanUser relationship

Using the rest API I am trying to get a list of users that share a common field in the “relationships” portion of a user’s returned data. Long story short, I’m trying to filter on the field “human_user_sg_production_manager_human_users” -> “id”. Below is the basic structure of an individual user. All my attempts using _search yield either “path.to.field” does not exist or invalid hash.

Any guidance would be greatly welcomed.

{
“data”: [
{
“type”: “HumanUser”,
“attributes”: {
“name”: “Users Name”,
},
“relationships”: {
“human_user_sg_production_manager_human_users”: {
“data”: [
{
“id”: 666
“name”: “The Guy that links them all”,
“type”: “HumanUser”
}
],
“links”: {
“self”: “blahblah”
}
},
},
“id”: 0000,
“links”: {
“self”: “/api/v1/entity/human_users/0000”
}
}
]
}