HTML Cleaner - Keep specifics links

[Perfecto]

Hi,

I made this regex to clean the HTML code and keep only the H, p, strong and b tags :

<div.*?>|<span.*?>|<figcaption.*?>|<img.*?>|<hl.*?>|</hl.*?>|</span.*?>|<picture.*?>|</picture.*?>|</div.*?>|<svg.*?>|<path.*?>|<figure.*?>|</figcaption.*?>|</figure.*?>|class.*?(?=>)|</path.*?>|</svg.*?>|<source.*?>|</source.*?>|(?<!\()<a.*?>|</a.?>(?!\))|<aside.*?>|</aside.*?>|rel=".*?"|target=".*?"|<header[\w\W]*header>|Share.*?(?=<)|Previous\ article|Next\ article

It works but I would like to go further by deleting the links without deleting those whose domain name would be in a whitelist.
How to do this ? Thanks for your help.

 

[EtaLasquera]

I wish you must create a list with "whitelist" and delete itens outside the whitelist.

 

[Perfecto]

I also need to remove the internal links while keeping the anchors.

<a\ href="/.*?</a>

This regex extract all internal link but how to keep the anchor and remove the link ?