Hi mikrotiks!

I am fresh and amazed by the mikrotik capabilities.
Now I have to create the following network setup and was wondering how to set it up. I understand and am able to setup the simple repeating process but I want to achieve a second network on another floor with its own IP range and own SSID to make it more private rather it being all the same network. But both nets will use the same ISP which is alright. The privacy just has to filter out the other devicea in plain view.

How do I achieve this:

ISP --- Router w/ WiFi SSID A (((--))) office devices IP-Range A
(((--))) Mikrotik as repeater but SSID B (((--))) private devices IP-Range B

How ist this possible? Preferably with its own DHCP for SSID B.

Also I would like to setup the repeating inside mikrotik for the best data exchange similar like crossband repeating. Is that possible, too? If so, how?

Thanks for any hints in the right direction!