Dear Mark,
You can do it easily in this way:
\version "2.22"
tune = \relative c'' {
\clef treble
r4^"A" \tuplet 3/2 { d8 d d } \tuplet 3/2 { d8 d d } d8 r8 |
r4^"B" r8 \tuplet 3/2 { d8[ d d] } \tuplet 3/2 { d8[ d d] } d8 |
}
\score { \new Staff \tune }
But I would recommend to do it as quoted below:
\version "2.22"
%sechzehnteltriolen
ST = #(define-music-function (x) (ly:music?)
#{
\set Voice.beamExceptions = #'( )
\set Voice.baseMoment = #(ly:make-moment 1/8)
\set Voice.beatStructure = #'(1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 )
\tupletSpan 8
\tuplet 3/2 { $x }
\tupletSpan \default
\unset Voice.baseMoment
\unset Voice.beatStructure
\unset Voice.beamExceptions
%\unset Voice.beamExceptions
#})
tune = \relative c'' {
\clef treble
r4^"A" \tuplet 3/2 { d8 d d }
\tuplet 3/2 { d8 d d } d8 r8 |
r4^"B" r8
\repeat "unfold" 2 { \ST { d8 16 ~ 16 8 } }
d8 \noBeam |
}
\score { \new Staff \tune }
Hope this helps!