Represent a list of tables in Jasper Reports

Question

I have the following collection in MongoDB

Collection

I want to create a list for each account for which I created a dataset with the following query

{ runCommand : { aggregate : 'case', 
                pipeline : [ { $project : { accounts : 1 }},
                             { $unwind  : '$accounts'}
                                     ]
           }
}

Now inside the list I want to represent the transactions array in a table. I am not able to figure out what dataset query should I use for it. Currently I am using this

{ runCommand : { aggregate : 'case', 
                pipeline : [ { $project : { accounts : 1 }},
                             { $unwind  : '$accounts'},
                             { $unwind : '$accounts.transactions'}
                                     ]
           }
}

But the result I get is wierd. I get 3 tables but each table has all the transactions in all 3 accounts. I think I need to group them somehow with accountNumber as it is unique to each account but I cannot figure out the corresponding mongo query. Need some help please.

This is the final result of my report