Their families may agree on politics, but when it comes to football, the Romney and Ryan families' college rivalry will be on display this weekend at the Notre Dame-BYU football game in South Bend, Ind.

Two of Romney's five sons, Craig and Tagg, who are BYU alumni, and Tobin Ryan, a Notre Dame alum and the older brother of Rep. Paul Ryan, will attend Saturday's football game together at the University of Notre Dame.

"This is probably maybe the only wedge issue between the Romneys and Ryans is tomorrow's game," Tobin Ryan told ABC News in a phone interview as he drove from Chicago to South Bend with his daughter Friday afternoon.

Tobin Ryan, who graduated from Notre Dame from 1987, will give Craig and Tagg's families a tour of Notre Dame, stopping at the grotto and Basilica and maybe even popping into Tobin"s old dorm Sorin College, where Knute Rockne once lived.

They will then attend an event, which will include some fundraising, with Romney-Ryan supporters from both Notre Dame and BYU at the LaSalle Grill in downtown South Bend, and Tobin Ryan and his 14-year-old daughter will sit with Craig and Tagg's families at the game Saturday afternoon.

Tobin's older brother Stan also attended Notre Dame and graduated in 1984, but despite the urging of his brothers to go to Notre Dame and being a Fighting Irish fan, Paul Ryan decided to attend Miami of Ohio.

"We put a lot of pressure on him to come to Notre Dame. That's for sure, and he just wanted to be his own man, and my mom took him to a number of schools in the Midwest, and he absolutely fell in love with Miami of Ohio," Tobin Ryan said. " But Notre Dame has a place in his heart."

Last year, Tobin and Paul Ryan attended the Notre Dame-USC game together with their two sons, and they were supposed to attend a Notre Dame game together this year, but as Tobin Ryan said, "Other things came up and made Paul's schedule a little busy."

So instead of watching the Fighting Irish face the BYU Cougars with his brother, the Republican vice presidential nominee, Tobin Ryan will take in the game with two of the Romney sons, who he hopes will be forced to wear a Notre Dame hat if the Irish win on Saturday.

"I'm sure there will be some good side bets and probably that loser will be seen on Twitter wearing the other team's hat," Tobin Ryan said. "I hope Tagg Romney will be wearing a Notre Dame hat."