How to fetch limited amount of users from Firebase - swift

Question

I am doing a card stack swipe app with users similar to Tinder.
I want to fetch a batch of 10 users from Firebase. I have used queryLimited(toFirst: 10) for this but later in my function i won't fetch the users who have already been accepted(swiped right). This means that if the first 10 users from Firebase already have been accepted nobody will be fetched. I want to fetch the first 10 users who hasn't been accepted.
Does anyone have a great solution for this?
Thank you.
FetchUsers code for fetching users from Firebase:
func fetchAllUsers(completion: #escaping (_ message: String) -> Void){
//User or advertiser?
Database.database().reference(withPath: "Advertiser").child(uid).observeSingleEvent(of: .value, with: { (snapshot) in
if snapshot.exists(){
myAdvertiserVar.advertiser = true
self.currentUserKind = "Advertiser"
self.otherUserKind = "Users"
}
else{
myAdvertiserVar.advertiser = false
self.currentUserKind = "Users"
self.otherUserKind = "Advertiser"
}
// Fetch
let query = self.ref?.child(self.otherUserKind).queryOrdered(byChild: "email").queryLimited(toFirst: 10)
query?.observeSingleEvent(of: .value) {
(snapshot) in
let g = DispatchGroup()
for child in snapshot.children.allObjects as! [DataSnapshot] {
let id = child.key
//If Already Accepted, don't fetch
g.enter()
Database.database().reference(withPath: self.currentUserKind).child(self.uid).child("Accepted").child(id).observeSingleEvent(of: .value, with: {(accepted) in
if accepted.exists(){
print("\(id) är redan Accepted")
}
else{
if myAdvertiserVar.advertiser == true{
let value = child.value as? NSDictionary
let username = value?["Username"] as? String
let occupation = value?["Occupation"] as? String
let age = value?["Age"] as? String
let bio = value?["Bio"] as? String
let email = value?["email"] as? String
let user = User(id: id, username: username, occupation: occupation, age: age, bio: bio, email: email)
self.usersArray.append(user)
}
else{
let value = child.value as? NSDictionary
let username = value?["Owner"] as? String
let occupation = value?["Location"] as? String
let age = value?["Rent"] as? String
let bio = value?["About"] as? String
let email = value?["email"] as? String
let user = User(id: id, username: username, occupation: occupation, age: age, bio: bio, email: email)
self.usersArray.append(user)
}
}
g.leave()
})
}
g.notify(queue: .main, execute: {
print(self.usersArray.count)
completion("Users list fetched")
})
}
})
}