iOS 26, using Swift, how can I group multiple Liquid Glass buttons into a single pill view?

In iOS 26, how can I group multiple Liquid Glass buttons into a single pill view instead of separate buttons that my code currently does.

Note that I need to use UIKit, not SwiftUI.

Below code:

import UIKit
import SnapKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let container = UIVisualEffectView()
        
        let effect = UIGlassContainerEffect()
        effect.spacing = 10
        container.effect = effect
        
        let uIStackView = UIStackView()
        uIStackView.axis = .horizontal

        uIStackView.addArrangedSubview(button(systemName: "arrow.uturn.backward"))
        uIStackView.addArrangedSubview(button(systemName: "arrow.trianglehead.2.clockwise.rotate.90"))
        uIStackView.addArrangedSubview(button(systemName: "speaker.wave.3.fill"))
        uIStackView.addArrangedSubview(button(systemName: "star.fill"))
        
        container.contentView.addSubview(uIStackView)
        uIStackView.snp.makeConstraints { make in
            make.edges.equalToSuperview()
        }
        
        view.addSubview(container)
        container.snp.makeConstraints { make in
            make.center.equalToSuperview()
        }
    }

    func button(systemName : String) -> UIButton {
        let config = UIImage.SymbolConfiguration(pointSize: 14)
        
        let button = UIButton()
        button.setImage(UIImage(systemName: systemName, withConfiguration: config), for: .normal)
        button.configuration = .glass()
        let padding = 15.0
        button.configuration?.contentInsets = NSDirectionalEdgeInsets(top: padding, leading: padding, bottom: padding, trailing: padding)
                    
        return button
    }    
}

Gives:

As you can see, each button is being rendered as separate instead of a single pill like view.

This article uses glassEffectUnion to achieve it in SwiftUI. How can this be done in Swift instead of SwiftUI?