The relationship between the Chicago Cubs and the rooftop businesses overlooking Wrigley Field sounds about as bitter as the Cubs-Cardinals rivalry. George Loukas, who owns three rooftop clubs and other businesses in the North Side Wrigleyville neighborhood, threatened to sue the the team if it erects billboards in the outfield that block rooftop views into the stadium. "We have a right to defend our position," Loukas said Friday. "Yes, we would go to court." He made his comments a news conference he and other rooftop owners held to present to the public an alternative to outfield signs the Cubs say they want to help pay for a $300 million renovation of the 99-year-old ballpark. They offered to let the Cubs place signs on their buildings and forego all the revenues the signs would generate.