Different time signature for different parts

[Tim Yang]

Hi,

I have a score here that the solo instrument and accompaniment have
different time signatures. The piece is from a Divertimento of
Giovanni Battista Bononcini.

The solo instrument has time signature 12/8, and the accompaniment
part is written as 4/4.  So the solo part can be seen as all triplets for a 4/4.
To complicate things, the solo has a partial measure at start with 2
eighth (triplet) notes,
which counts 2/3 beat for the 4/4, but the accompaniment part is
written as a 1/2 beat
rest at the same place. The human performer of the accompaniment is expected to
interpret it correctly and start at the main beat.

Is is possible to express this score in Lilypond?

Tim Yang