What's the solution to this sibling rivalry situation ?

Sam and Lola have been divorced for years . Sam and Lola have a son, Benny . Lola has a son, Robbie, from a previous marriage . Benny and Robbie are having serious trouble getting along . Sam and I are roommates . Benny spent last week at our house to avoid Robbie . Sam turned Benny over to Lola, and a few hours later, Lola and Benny were standing at our front door . Benny got into a big fight with Robbie . He threatened to walk to our place from Lola's home, a distance of five miles . Lola wanted to turn Benny over to Sam . We're always happy to have Benny, but we had to spend money we couldn't spare to take Benny home in a taxi the next morning . Since Benny spent the week away from home, why can't Robbie spend a few days someplace else ? Is turning Benny over to Sam the only solution ? What else can Sam and Lola do ?