Does epplus ExcelRichText have a property to identify where in the string the rich text occurs?

Question

If I am reading a string like this 2222 range.RichText has two ExcelRichText objects

But how can I know which of the "2" characters in the input string are the ones that correspond to the ExcelRichText objects? I'm hoping for a Position or Index property or something like that but can't find one.