Trading places makes a United City
It might be just symptomatic of the A-League.
In the world's more established leagues clubs' fans vehemently object when one of their favourites moves to a rival outfit but not in Australia.
As Adelaide United prepares to face Melbourne City in an elimination final at Hindmarsh Stadium on Sunday the number of players, coaches and administrators that will know the inner secrets of each club is frightening.
Remarkably there are 23 players that have played for both clubs.
Adelaide must also thank City for playing a huge part in helping the Reds secure the 2016 titles under then coach Guillermo Amor.
The then swap deal - Adelaide's Osama Malik for City's Stefan Mauk - was the catalyst for Amor's Reds to win the double.
Mauk was driving the Reds charge as United belted City 4-1 in the knockout semi before winning the grand final in front of more than 50,000 fans at Adelaide Oval in 2016.
However to some extent City exacted revenge.
City now owns a bonafide Adelaide United legend and an ex-Reds prodigy is now the captain.
Adelaide's record games-holder Eugene Galekovic. The former United captain, who wore the armband during the club's Premiership and Cup victories, is in exhilarating form for City.
Galekovic's form for City was rewarded with the club's best player award on Saturday, adding to his two Reds club champion awards and three player's player trophies.
Former Red Rily McGree, 20, won the club's golden boot with seven goals in tandem with a former City player Craig Goodwin who won it for Adelaide with 10 goals to his name.
Scott Jamieson, 30, is the City skipper.
Both clubs are lucky soccer fans usually don't follow individuals like WorldTour road cycling fans do because if they did Hindmarsh would be chaotic if they supported their personal favourites.
Incredibly City's squad is just four players short of fielding a potential ex Adelaide United II against Adelaide United in the do-or-die final on Sunday.
On the other hand Adelaide just has three players - at the moment - that were ex City boys.
The most recent ex City boy being centre back Michael Jakobsen, 33.
Goodwin, 27, joined Heart/City in a measure to be noticed when the Reds then youth set up bypassed the clever left winger.
Goodwin believed in himself, packed up, went to Melbourne to join Oakleigh Cannons, worked at KFC to make ends meet before Heart (now City) signed him up.
He was best on ground on debut in 2012 in a scoreless draw with Victory.
Michael Marrone, 32, slipped over to City's debut squad becoming the 14th player to sign for the club after he originally signed for North Queensland Fury which went bust in 2010.
Marrone's Heart/City initial season was brilliant.
Italian Serie A club Cagliari were about to sign him but Heart's transfer demand forced the Sardinians to rethink before they gave up on the deal.
Marrone had a stint at China's Shanghai Shenxin before returning to Adelaide in 2014.
Former Melbourne City players that are now with Adelaide United:
Former Adelaide United players that are now at Melbourne City:
Iacopo La Rocca
Players that featured for both clubs that are no longer there:
Stefan Mauk (Brisbane Roar)
Bruce Kamau (Western Sydney)
Ruon Tongyik (free player)
Marcelo Carrusca (West Adelaide NPL)
Osama Malik (Al-Batin, Saudi Arabia)
Iain Ramsay (Sukhothai FC, Thailand)
Paul Reid (retired)
Ben Garuccio (Hearts, Scotland)
Kristian Sarkies (Beaumaris, Victoria)
Michael Zullo (Sydney FC)
Jacob Melling (Central Coast Mariners)
Marc Marino (Campbelltown City, SA)
Eli Babalj (free player)
Coaches or administrators that worked for both clubs:
Michael Valkanis (ex City assistant and ex Reds interim coach and player)
Luciano Trani (ex City and ex Adelaide assistant)
Michael Petrillo (ex Adelaide chief executive and football director, now City football director)