IOS – How to selectively share app purchases among iOS devices using iCloud

I have three iOS 6 devices among which I would like to selectively share apps. I have an iPhone and my wife has an iPhone and an iPad. I understand that by using a common Apple ID for the App Store, we can purchase apps once and use them on all three devices; no problem there. However, I'd like to be able to manage things in a slightly more advanced way, if possible. Here's what I would like to happen:

• If my wife purchases an app on her iPhone, it will automatically download to her iPad, and vice versa.

• If my wife purchases an app on one of her devices, I don't want it to automatically download to mine, and vice versa. While there might be a lot of software that we might want to share, there's also a significant amount of content that we won't want in common. I would like the sharing of these apps to be a more manual process (i.e. after I purchase an app, she could go to the App Store and choose to download it to her device(s)).

• In my experience, using iTunes for managing multiple devices in this way is a bit clunky, so I would like to have a no-computer-in-the-loop approach. Notably, I have seen other questions that suggest using iTunes Home Sharing to share applications among different devices. It's not clear that this is a fit for my situation, as I don't have multiple computers, only multiple iOS devices.

I'm not sure whether this sort of setup is possible. As a start, I have set up a common Apple ID for our store purchases and separate iCloud accounts for my wife and I, allowing us to segregate our backups. I'm not sure whether it's feasible to achieve the selective automatic synchronization between devices that I'm looking for; I was hoping that iCloud would allow this.