Hello, this is not possible. Of course you can mimic that behviour using afterGrace.
Cheers, Valentin 03.02.2022 14:05:32 Rip _Mus <ripetizioni.mus...@gmail.com>: > Good evening everyone, > > I am new to the language of Lilypond, so I would like to ask you for advice > that you will certainly have more experience. > > To your knowledge, is it possible in a pitchedTrill to insert a chord (or a > bichord) in the position between brackets (auxiliary)? Each time I try, Lily > only inserts the first of the notes entered. > > > Thank you, see you soon > > Rip_mus