 
  
  const arr = str.split(/(?<=[A-Z]), /);
// или
const arr = str.match(/[^,\s][^,]*, [^,]+/g) ?? [];
// или
const arr = str
  .split(', ')
  .reduce((acc, n, i) => (
    (i & 1) || acc.push([]),
    acc[acc.length - 1].push(n),
    acc
  ), [])
  .map(n => n.join(', '));