第一个that后面跟的从句是goes with a welcoming cup of tea or coffee,是用来补充the ritual interaction的,后面一个that是用来补充the ritual interaction that goes with a welcoming cup
of tea or coffee的,意思是这种以热情的茶或咖啡为伴的社交礼仪可能是他们国家的一种习俗。下图能帮你更好的理解句子,第一个括号的分句修饰下面有点点着重号的the ritual interaction,后面括号的分句修饰下划波浪线的句子。希望能帮到你!