Hi @filchristou I’m afraid the short answer is no. GMT.jl creates PS fig files that are later converted to raster formats. I have no idea what Makie intermediate steps do but they certainly cannot append to the PS file generated by GMT.jl.
However, CairoMakie uses Cairo that can produce PostScript so it’s not inconceivable that CairoMakie could one day append to an existing PostScript file, but … not today.