In football, clubs aren't standalone entities. In addition to many clubs having close ties with companies (such as Philips Sport Vereniging, better known as PSV Eindhoven, or lowly Airbus UK in the League of Wales), there are plenty of clubs that have links with other clubs. Manchester United, as many know, have a relationship with Royal Antwerp, while elsewhere both the Metrostars and Austria Salzburg have been purchased by Red Bull, controversially changing team colours and renaming the sides to Red Bull New York and Red Bull Salzburg respectively.
So what do those relationships mean? Well, Antwerp's case is clear - United regularly send out youngsters on loan to aid their development. For the Red Bull sides, things have yet to fully materialise. It is possible that players could move between the sides, and with a common ownership I wouldn't be too surprised to see that their financial status mirror each other. Regardless, it's a tricky situation.
This becomes pertinent when regarding the game. No simulation of world football would be complete without organising relationships between the clubs, and while each individual case is often complex, there are general factors that I can use.
The first relationships I have in the game are the obvious. Rivalries exist between clubs, of differing strengths and reasons, be they sporting, political or simply based on location alone (a number of rivalries encompass all three, of course). Clubs can be Successors, in that they were formed out of an existing or collapsing club. FC United and AFC Wimbledon are two famous "successor" clubs formed by fans who feel the original side have mistreated them for too long. AFC Telford United or 1.FC Lokomotiv Leipzig are sides borne out of the ashes of clubs who have fallen under financial strain. In these situations there is often great debate as regards the ownership of the history of the original club - AFC Wimbledon and Milton Keynes Dons both claim the history of the old Wimbledon. Personally, I side with AFC Wimbledon (with a little foot in the "Wimbledon are dead and there are two new clubs" camp) but if the game's to be encyclopaedic, I need to find an official answer.
And of course, there are mergers. These "successor" clubs are formed out of a merger of existing clubs, or perhaps just absorbing a single club into the existing powerhouse. Kinda like Loco Roco. Rushden & Diamonds are a merger club, formed from the non-league sides Rushden Town and Irthlingborough Diamonds.
The game will not feature any mergers, splits or new clubs itself during the course of play. The technicalities of such features are pretty simple, but club names are hugely complex around the world. What applies in England will not stand in Germany, and is utterly useless in Brazil.
You can, however, form your own clubs in the game, at any point (provided you have the cash).
Feeder Clubs will be in the game, in a greatly simplified format at first. As described above, a feeder club link will allow for the parent side to send their players out on loan to the feeder, adhering to all the transfer rules of the governing bodies involved. The parent side can also have first option on any player in the feeder club. As the intricacies of feeder clubs become more apparent, I'll be expanding on the situation, but a basic implementation is a must. Feeder sides such as Real Madrid Castilla, which are essentially part of the whole Real Madrid club, will be implemented as second or third sides of the main side.
And lastly, clubs can be linked Financially, enabling potential situations like the Red Bull Empire.
And remember from Star Wars - empires are the bad guys.