Simply use PgcDemux to demux the menu A into elementary streams (video, subs for button highlights). Do again for another menu B with wanted audio. Use MuxMan to combine video, subs and audio.
In DRMP, menu to be replaced, Preview window, export buttons and color scheme into files. Import the MuxMan VOB file in Programs pane using “Replace block”. Now import the original buttons and color scheme file back in.
And that’s it.