Here's a Glee set:

Finn, Rachel, Kurt, Artie, Quinn and Mercedes are hanging with

Mariela, Liam, Monika, Kale and Emmy.

Meg, Jo, Beth, and Amy could hang out with brothers Ron, Russ, Stan, and Henry.

Mary, Laura, Carrie, and Grace move away from the prairie and meet James, Jack, Barney, and Paul.

Barney?!

Eureka:

Jack, Allison, Douglas, Holly, Josefina, and Zane give us:

Werner, Henry (ha!), Dean, Ava, Charlotte, and Grace (ha!)

I don't know why this thought entered my mind, but I did the Spice Girls (Melanie [x2], Emma, Victoria, and Geraldine [Geri]).

Sisters: Bernadine, Adele, Elvira, Charlotte, Maria

Brothers: Roderick, Karl, Kurt, Noah, Bert

Brilliant idea, and great sets so far!

Robb, Sansa, Arya, Bran and Rickon, meet your new siblings Donn, Reba, Eiley, Bert and Darrick.

(I couldn't resist another Bert!)

Okay so I'm fasinated by the Duggars. There is not one naming style among them, though you could put them into categories. I decided to do it in sets of six, three, and four for this game though. Note then whenever a real live sibling or somehting similar showed up for the right gender I chose it. Here goes:

Joshua, Jana, John-David, Jill, Jessa, and Jinger could have siblings James, Jordana, Jed, Anna, Grace, and Jolene. 

Joseph, Josiah, Joy-Anna, Jedidiah, Jeremiah, and Jason could have siblings William, Japeth, Jana, Jesse and Jamin.

James, Justin, and Jackson could have brothers Joseph, Clinton and Arden. 

Johanna, Jennifer, Jordyn-Grace and Josie could have sisters Janna, Elizabeth, Caroline, and Janette.

I didn't repeat names but William seemed to show up alot. There are so many different styles though! 

They're not actually people, but this is what I keep coming up with when I try to think of a famous set of names.

Faith, Hope and Love have sisters Serenity and Grace and brother Forest.

On the other hand Faith, Hope and Charity have sisters Grace and Mercy and brother Merritt.

Francis, Reese, Malcolm, Dewey, Jamie gives you:

Brothers:

Graham, Eugene, Paul, Chance, & Kevin

Sisters:

Brooke, Casey, Erin, Tess, & Stella

Charmed: Phoebe, Prudence, Piper, Paige, Cole, Leo

Ivy, Serenity, Peyton, Jade, Pete, and Max  lol

or

Buffy the Vampire Slayer

Buffy, Angel, Xander, Willow, Cordelia, Spike

Bettina, Gabriel, Jagger, Harper, Rowena, Blade

lol

Ok!

William, Percy, Fred, George, Ronald, and Ginevra (sorry, I had to leave out Charlie) now have brothers Eugene, Hugh, Rupert (like Rupert Grint!), and Charlie (that's funny!) and sisters Mathilde and Grace.

James, Albus, and Lily have brother David and sisters Charity, Wren, Lina, Charlotte, and Ava

Mary-Kate and Ashley now have little siblings! Ellis, Daron, Miller, Kinsley, Jodi, and Maddison