WordPress on LAN – Works on host mac but not on other network macs

I am trying to set up an intranetsite with wordpress that should be available to everybody on the local network. At first things went smoothly: install MAMP, make database, install WordPress. The website looks and works alright on my own mac at localhost:8888

But the others on the network only get to see the startpage without CSS and the links don’t work. I think the problem has something to do with the port that Apache uses. I have tried the following, without success:

– Change the WordPress Address URL and Site Address URL in WordPress>Settings>General. This doesn’t work because WordPress forgets where it lives and can’t find any pages anymore. The only way out is to reinstall.

– Change the port for apache in MAMP>Preferences>Ports. Apache gets port 80 and MySQL gets port 3306. This doesn’t work either because https://localhost now produces a page that says: “It works” which means that it is looking in the folder where the Mac’s standard website is hosted: library/webserver/documents

– Change the document root in MAMP from /Applications/MAMP/htdocs to /Library/WebServer/Documents. This doesn’t work because localhost/index.php now shows the content of the file rather than executing it.

I usually solve my own problems with a little help from Google but this one won’t go away. I spend almost the whole day on it and I’ve run out of ideas. Could someone please help or point me in the right direction?

TIA
Michiel