From the excellent BBEdit User Manual;-)
menu Help > User Manual
Organizing Scripts
Items in the Scripts menu and Scripts palette are displayed in alphabetical order by default, but you can force them to appear in any desired order by including any two characters followed by a right parenthesis at the beginning of their name. (For example “00)Save All” would sort before “01)Close All.”) For names of this form, the first three characters are not displayed in the window.
You can also insert a divider into the Scripts menu by including an empty folder whose name ends with the string “-***”. (The folder can be named anything, so it sorts where you want it.)
Note Any dividers you add will appear in the Scripts menu, but not the Scripts palette.
Furthermore you can google "github applescript bbpackage" and see how to wrap your scripts in a bbpackage.