Higher Order Multiples refers to triplets, quads, quints and more. There are networks to support these superstar parents.  About 80-90 sets of HOMs are born in Australia every year.

Australian Multiple Birth Association   
AMBA not only supports families with twins - it also provides invaluable support to families who are expecting or rearing three, four or more children of the same age. 

MOST online (US)
MOST is a network of families with triplets, quadruplets and more that provides information, resources, empathy and good humor during pregnancy, infancy, toddlerhood and school age.

Triplet Connection (US) 
This site also provides support for multiple birth families.

4Tunate Boys (US)
A unique insight to what life is like with quads - this is an amazing 'blog' website.