MusixTeX. Straight line slides (how to)

[George Svetlichny]

In typsetting classical guitar music I need to create a straight-line
slide from one note to another (indicates either a glissando, or just
the fact that the left-hand finger that is fretting the first note, is
to be carried along the same string, without sounding, to the position
of the second note).  This slide should work just as a slur (\isslur
variety) except that it must be straight and not curved. I was unable to
create this effect and would appreciate any suggestions.

George Svetlichny