is there a way to change the CAS APEREO collection structure?

Question

I am planning to implement CAS with MongoDB authentication and also planning to use existing MongoDB collection which is not following the expected Document scheme as mentioned in apreo documentation.

As per documents,

Accounts are expected to be found as such in collections:

{
    "username": "casuser",
    "password": "34598dfkjdjk3487jfdkh874395",
    "first_name": "john",
    "last_name": "smith"
}

is there way to customize the username and password attributes something like below

{
    "_id" : "000debf7-ee17-42ec-b267-9028b721cd57",
    "firstName" : "Steve Ward",
    "lastName" : "Steve Ward",
    "emailAddress1" : "test@inter.com",
    "status" : "active",
    "users" : [
        {
            "userName" : "weldoneinc",
            "password" : "KJH8u3lRYvm82EbiGjKZs7exPbY=",
            "createUser" : "TEST",
            "createDate" : ISODate("2020-05-22T15:28:54.439+0000"),
            "updateUser" : "TEST",
            "updateDate" : ISODate("2020-05-22T15:28:54.439+0000")
            }
            ]

}