Complex sentence: This caused an immediate reaction from the three main supporters groups that had created the original competition and prompted them to form a legal entity called the Cascadia Cup Council, whose sole purpose was to obtain and retain the legal rights to the name "Cascadia Cup".
Split into simpler sentences: This caused an immediate reaction from the three main supporters groups that had created the original competition. This prompted the three supporters groups to form a legal entity called the Cascadia Cup Council, whose sole purpose was to obtain and retain the legal rights to the name "Cascadia Cup".