Is it possible to have an invisible note indicator in the text?

Two sequences of notes within one displayed series aren't so bad, assuming a need to present annotations and textual notes on the same page.  (The idea came from this thread.) A great deal can be done to separate the series visually, although not geographically on the page. E.g., the textual notes can be in a different typeface as well as being given different indicators. Whether the custom indicator in the text is always the same or whether it has a little series of its own is independent of the indicator in the second series of actual notes. The indicator in the notes can be even be deleted and yet the note remains! In this case it might be desirable to substitute something else, e.g. a line number. Here's an example of 2 sequences within one display series. I wouldn't really mix the custom indicator * with the line number or  blank indicator alternatives shown below.