Disclaimer: Suzanne Collins owns everything.
Before the reaping if you had asked Prim what first came to mind after hearing "Marius Mellark" she would have come up with:
Super-strong
Arrogant
Wrestler
Baker's Son
Likes squirrels
Tall
Gale's enemy
If you had asked her what first came to mind when hearing "Brice Mellark" she would have said:
Quiet
Smartish
Likes Squirrels
Super tall
…he bakes bread.
If you had asked the Mellark brothers what they thought about Primrose Everdeen they would tease Peeta about his crush on Katniss, Prim's older sister.
But somehow, fate stepped in. Doesn't it always? Primrose Everdeen gained a way to help get over her sister's certain death; and the Mellark brothers got the little sister they never had. And this is how.