What is the Din regarding someone eating meat at a table of people eating dairy? What if he is not actually eating over the table, but just sitting next to it?
It is permitted, provided that a heiker is made (for people who know one another).
This means that something must be done to ensure that each person remembers not to eat from the other’s food, such as using different tablecloths, or placing something between them that isn’t part of the meal.
Gemara, Chullin 108a; Shulchan Aruch, Yoreh De’ah 86.