Yes, it's not possible. This is the very same way my wife and I were running bills for years, and yes, that's why I didn't move to Simple due to that feature not being there.
Interesting. So, if you forgive my ignorance once more: How do you use a Simple account? I mean.. What can you do with it? Grab cash from an ATM only? Write (oh my god, please say no) checks backed by that account?
In other words: If you cannot transfer the money to a different account, how do you USE the money at all?