What’s the difference between a Harlequin continuity series and your own series?
Harlequin continuity series are usually eight books, all written by different Harlequin Presents authors, set in the same world and featuring some overlapping characters.
My own series in Presents are usually only two books and maybe a connected novella, and are often referred to as “duets.” You can see if a book is connected to other books in the Connected Books section of each book page.