Meant to link the article. Here ya go, it's from 2013;
http://www.theofficialreview.com/nfl-cross-ownership-rules/
Also, from an article about our Bills being up for sale;
https://www.buffalorumblings.com/bills-news-notes/2014/3/26/5548174/nfl-ownership-rules-buffalo-bills-sale-ralph-wilson
"Cross-ownership rule
Team owners are now allowed to own teams in multiple major sporting leagues, but those teams need to be in the same city (unless there is no NFL team in the other city). Buffalo native Jeremy Jacobs owns the Boston Bruins, but would have to sell that team in order to become the majority owner of the Bills. Seattle Seahawks owner Paul Allen can also own the Portland Trailblazers because Portland doesn't have an NFL market.
Ironically, this rule change was opposed by Ralph Wilson in 1997, when NFL owners lifted restrictions on other sports' owners from purchasing an NFL franchise. To that point, NFL owners collectively wanted their team owners concentrating on football."