I’m using a .tex file as a subsection in my main .tex file. In the main.tex file I have:

documentclass{article}

usepackage{subfiles}

begin{document}

subsection{Section title}

subfile{sub.tex}

subsection{Section 3 title}

end{document}

The sub.tex file is similar to:

documentclass[main.tex]{subfiles}

begin{document}

subsection{Section 2 title} 

.
.
.

end{document}

I want to keep the section numbering when I create a PDF of the main.tex file, but I’d like NOT have the subsection numbering when I generate a standalone PDF from the sub.tex file.

I searched around and found somethings that kind of did what I wanted, but I was hoping, in keeping with the subfiles package, there was an elegant way to do this?