TBS, not a problem, you can Bi-link panels together, normal practice fo ajoining buildings, but in your project, would suggest keeping cost down, with good EN control panel and detection, like Apollo....and interface wired Acio mains smokes into a seperate zone on the control panel, this will show the activation is from fats. Aico do a input, and an output unit, so the system will work Bi direction, sounding aicos if fire is in cafe, and cafe with zone indication, if activation is from flats.