Here's the story of a stallion named Hoof Brady, an Earth pony, who was raising three sons (themselves Earth ponies) of his own as a single, divorced father living in Manehattan.

Here's the story of a mare named Carol Mane, a Pegasus, who was raising three daughters of her own (themselves pegasi) as a a single, divorced mother living in Cloudsdale.

Till one day when these two families met each other as they both had moved to Ponyville. Hoof Brady and Carol Mane decided to marry each other and adopt each other's foals, and they knew, the somehow formed a family, and that's how they became the Pony Brady Bunch.

The sons of Hoof Brady: Greg Horseshoe Brady, Peter Tails Brady, and Bobby 4 Legs Brady.

The daughters of Carol Mane: Marsha Moonlight Mane, Jen Jet Stream Mane, and Cyndi Comet Mane.

Their family maid and cook (and friend): a female unicorn named Alice Amazing Horn.