Babysitter advice please

We have a sitter that watches my 6m daughter in my house while I work part time. My work has given me additional maternity leave. I don't want to hunt for a sitter after this leave (now through eoy) so I offered one of my best friends to watch her 6 week old 3 days a week. So my sitter will still come to my house 3 days a week to help with my friends daughter. This keeps my sitter employed, I don't have to hunt for a new sitter come jan 1, and my friend can delay using a day care. Win win win, right? I want the sitter to be completely responsible for my friends daughter while I still can use my time off with my daughter. We need to work on her sleeping (whether that be sleep training or just working on falling asleep without the bottle) However, I feel like I'll end up doing the majority of the work with both, be distracted, and not get my QT with my daughter. How can I make sure I still am getting the time with my daughter to work on her napping schedule/routine?