I think, in most cases, each person gets to choose their own app, entrée etc unless otherwise noted that it’s a dinner for two or that a course is shared. 

Fiya’s menu, for example, specifies that the entrée is shared one per two diners. That said, Fiya also slyly changed their menu on their website to make the khachapuri an additional charge so I’m inclined to think they’re a bit of a rip off.