Charlie thanks!
I went with your suggestion, but my own way.
Seems there is no easy way out not getting some sort of mix box.
Found a cool looking, non-powered (!) small mixer that has impedance adjustment and bunch of other, perhaps useful buttons. Pokket Mixer Mini DJ Mixer...

https://www.youtube.com/watch?v=xv6OU5Oc1ng

Found a pre-owned cheap. Will post back with results smile