Obviously if two teams play on the same table/board/pitch then they must have fixtures that are opposite each other (when one team is at home, the other, paired team, is away). When generating fixtures these paired teams need to be dealt with first. After these are dealt with it is worth bearing in mind that it might be worth pairing up other teams (they don't need to be told about this). For example, if two pubs/clubs in the same street have one team each, pair them up. Firstly, there will then only be one match in that street on a match night and secondly, if one of the venues has to close for a few weeks for, lets say refurbishment, then the matches can still go ahead at the other venue. Maybe this is going too far, but it's just an idea worth bearing in mind.
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