When the waiter comes to take orders you can tell the waiter seperate checks please . That is what me and my coworkers do. So everybody knows that they are supposed to pay for whatever they consume.
It depends how big the group is and how intimate or close relationship you have with ther people you are with.
Me too none of my relatives who are younger than me are allowed to pay when I am there.
I like to treat my good friends all the time.