Spain could form a division without giants Real Madrid and Barcelona, Sevilla president Jose Maria del Nido has warned.
The country's top two tiers have opened discussions over creating a similar division to that of the Premier League.
However, one of the main bones of contention is the distribution of television money, which clubs currently negotiate individually.
That is contrasting to the Premier League, the German Bundesliga and France's Ligue 1, where collective deals are struck and revenue shared out.
"The clubs have to impose on the big two the conditions in play and if they don't accept them, no problem, we will have a league of 18 teams and they will have a magnificent one of two," Del Nido told the club's official website .
"This is a cake in which everyone participates and our decision will be radical.
"It is our responsibility to make sure it (the league) doesn't become a fight between only two teams."
Real and Barca, two of the world's richest clubs, rake in half the available cash with deals worth about €150million (Ј121.6m) a season.
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