Using the same .bib file for appendix

I have a main.tex file, an appendix.tex file and a ref.bib file.

My main page has references from the bib file, and I want the references in the appendix to be also referring to the ref.bib file without showing the references at the end.

Also if I add bibliography{ref} to my appendix.tex the references shows at the end and not in the references of main.tex. (I want all the references to be shown at the end of main.tex.)

Now I know there may be similar questions like:
use the same bibliography bib file for two latex source (main and appendix) But the answer is vague. It says use the xc package. Unclear instructions. Tried adding the code and failed.

What should I do?