JUPITER, Fla. — The Republican National Committee promised an “evening reception with Donald J. Trump” last March at his Mar-a-Lago resort in Palm Beach, Fla.

A contribution of $2,700 toward the president’s re-election would get you in the door. Two seats for dinner were on offer for $25,000. And there was a third option: for $50,000, dinner for two and a photo with Mr. Trump.

Cindy Yang was determined to get the photo.

But there was a hurdle. The invitation limited campaign contributions to $5,400 per person, so Ms. Yang, a Chinese immigrant who had set up a string of day spas in Florida and was active in groups backed by the Chinese government and Communist Party, needed others to chip in.

Over the weeks leading up to the event, at least nine people in Ms. Yang’s orbit, some of them with modest incomes, made donations at exactly $5,400. She ended up at the dinner.