Hi Jeff, You can hide part of a marker set by selecting the markers you want to show (maybe using the select connected shortcut "sc" as described earlier) then use invert selection (main window menu Select / Invert, or shortcut "is"), then use path tracer menu entry Actions / Hide markers (or shortcut "ha" for hide atoms). Tom Jeff wrote:

I don't suppose there's a way to hide only a portion of a marker set (just keep one filament visible out of 10, for instance)

-Jeff