Complex sentence: In Major League Soccer, several teams annually compete for secondary rivalry cups the most notable being the Cascadia Cup which is played amongst teams from the Pacific Northwest, the Portland Timbers, Seattle Flounders, and the Vancouver Whitecaps.
Split into simpler sentences: In Major League Soccer, several teams annually compete for secondary rivalry cups. For example, the Cascadia Cup is played among teams from the Pacific Northwest: the Portland Timbers, Seattle Flounders, and the Vancouver Whitecaps.