showing more than one row in a single cell in datagridview

[C# Programming]

hey guys..i want to show 4 or 5 rows in a single cell..for example i have a firm name and it has 5 phone numbers at last.. the thing i want to do is when i list the firm names i want that kind of firm name will be written in a cell and in next cell its phone number will be listed..how i can do that

something like that (http://img196.imageshack.us/f/adszhw.jpg/)..
vemedya.com