How to customize collection view flowlayout cell

Question

I am creating a movie ticket app using collection view. I'm stuck arranging the seats in a collectionView. How to customise the custom flow layout? I want a particular amount of seats in specific rows of the collection view cells

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
  if collectionView == leftCollectionView {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "leftcellid", for: indexPath) as! LeftSideMovieCollectionViewCell
    let selectedseat = leftsideArray[indexPath.row]
    if selectedSeatArray.contains(selectedseat) {
      cell.leftMovieSeatImageView.image = UIImage.init(named: "seatfulled")
    } else {
      cell.leftMovieSeatImageView.image = UIImage.init(named: "seatblank")
    }
    if indexPath.row == 16 || indexPath.row == 17  ||  indexPath.row == 12 || indexPath.row == 13 {
      cell.leftMovieSeatImageView.isHidden = true
    } else {
      cell.leftMovieSeatImageView.isHidden = false
    }
    return cell
  } else if collectionView == RightCollectionview {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "rightcellid", for: indexPath) as! RightSideMovieCollectionViewCell
    let selectedseat = rightsideArray[indexPath.row]
    if selectedSeatArray.contains(selectedseat) {
      cell.RightMovieseatImageView.image = UIImage.init(named: "seatfulled")
    } else {
      cell.RightMovieseatImageView.image = UIImage.init(named: "seatblank")
    }
    if indexPath.row == 18 || indexPath.row == 19  ||  indexPath.row == 14 || indexPath.row == 15 {
      cell.RightMovieseatImageView.isHidden = true
    } else {
      cell.RightMovieseatImageView.isHidden = false
    }
    return cell
  } else {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "maincellid", for: indexPath) as! MainCollectionViewCell
    let selectedseat = vipSeatArray[indexPath.row]
    if selectedSeatArray.contains(selectedseat) {
      cell.mainSeatImageView.image = UIImage.init(named: "seatfulled")
    } else {
      cell.mainSeatImageView.image = UIImage.init(named: "seatblank")
    }
    if indexPath.row == 43 || indexPath.row == 42 ||  indexPath.row == 34 || indexPath.row == 33  {
      cell.mainSeatImageView.isHidden = true
    } else {
      cell.mainSeatImageView.isHidden = false
    }
    return cell
  }
}

Here I have taken three collection views. I have hidden the particular cells. I don't know how to modify this. Can it be done with a single collection view? Any suggestions will be appreciated.