I have a list of people:

Column A:

person A,             
person A guest,       
person B,            
person C,            
person C guest,     
...

Column B:

1,
1,
2,
3,
3,
...

So in column A there is the person's name, column B gives a person a unique ID (the same id for their guest so we know that they are together).

Now pretend we have a list of 100 people (also note that not all persons have guests) and we have to seat them. We have a list of tables (for example 10 * 4 person table and 10*6 person tables). We have to randomize that each person is assigned to a table and the guest is seated on the same table.

What is the best way to do this? (it is also needed that I can generate this 4 times in a row without the same results, so when during the 4 courses of the diner the person are switching tables but not losing their guest).