Mongo Map-Reduce $sum with condition in query

Working with Data
1

I have requirement to update the data based on the inputs using recordID, each recordID has count of associated records.
since associated records has huge volume of data , I wanted to control the number of update based on the associated records count via configuration.
So in the query, i want to sum the associated document count and should not cross limit configured in property.
I wanted to fetch the records using $sum operation in the map-reduce query but not sure how to add the criteria.

{ 
    "_id" : ObjectId("5f8f52168"), 
    "recordID" : "11989", 
    "count" : NumberInt(5)
}
{ 
    "_id" : ObjectId("5f8f52148"), 
    "recordID" : "2561", 
    "count" : NumberInt(10)
 }
{ 
    "_id" : ObjectId("5f8f52038"), 
    "recordID" : "57546", 
    "count" : NumberInt(30)
}
{ 
    "_id" : ObjectId("5f8f52138"), 
    "recordID" : "12623", 
    "count" : NumberInt(40)
}
{ 
    "_id" : ObjectId("5f8f52188"), 
    "recordID" : "199429", 
    "count" : NumberInt(50) 
}
{ 
    "_id" : ObjectId("5f8f52148a"), 
    "recordID" : "12793", 
    "count" : NumberInt(60), 
}

Example1: Let’s say when totalcount<=50) I need to fetch the documents, in which total count sum less than or equal 50 (totalsum<=50), it should return below documents.

count <=50 ( count" = 5 + 10 + 30 )

{ 
    "_id" : ObjectId("5f8f52168"), 
    "recordID" : "11989", 
    "count" : NumberInt(5)
}
{ 
    "_id" : ObjectId("5f8f52148"), 
    "recordID" : "2561", 
    "count" : NumberInt(10)
 }
{ 
    "_id" : ObjectId("5f8f52038"), 
    "recordID" : "57546", 
    "count" : NumberInt(30)
}

Example2 : when totalSum<=20, query should return below documents.

count <=20 ( count : 5 + 10 = 15 )

{ 
    "_id" : ObjectId("5f8f52168"), 
    "recordID" : "11989", 
    "count" : NumberInt(5)
}
{ 
    "_id" : ObjectId("5f8f52148"), 
    "recordID" : "2561", 
    "count" : NumberInt(10)
 }