\ifdefined\directlua\input luaotfload.sty\fi

\directlua{
  inspect(fontloader.info"cambria.ttc")
}

\font\subfontone="file:cambria.ttc(0)" at 42pt
\font\subfonttwo="file:cambria.ttc(1)" at 42pt

\subfontone foo bar baz \endgraf
\subfonttwo foo bar baz \endgraf
\bye