This might be an XY problem[1].
In general, Inno Setup is designed to install a single application. With that said, you could create a "stub" installer with Uninstallable=no set and custom code to extract sub-installers and have the user select which one. I don't have a "working sample" of that to offer, though. If you want to do it, I would recommend reading through the Inno Setup documentation[2] to familiarize yourself with how it works and how you can customize various aspects of an installer.