As already stated, there are a lot of questions that need to be answered for anyone to give you some clear pointers.
For starters (as mentioned above) we need to know the relationship between the two circuits and whether they can be interconnected. If you don't know whether or not they can be interconnected, don't guess - just set out what you can so we can help you get answers. Your given diagram sort of starts along this line - with the sources and loads ... but the switch portion doesn't add anything useful.
Another thing is to be careful about making design decisions too soon ... and understanding the difference between what you
want to do and what you
need to do. Some things you may
want to do might not be things you need to do - likewise, some of the things you might
need to do may not be things you want to do.
Sometimes people are reluctant to share the full details about their project - and while that is understandable, it might be necessary to share a little more than you are comfortable with to get the answers that you need. Some members here might ask more than seems necessary, but it might be for a reason that you had not even considered. Either that, or from simple curiosity. (We are a curious bunch
)