SEO for websites with similar content

We have 3 businesses, located in different areas, with different names. They have different domains, and do not cross reference each other.

The business is the same function (medical), and branded differently, however to make things easy we triplicated the main website. Google now ommits the 2nd and 3rd business (the least busy) when googling. I have checked and the pages are on Google, however it omits them from search results.

Is it sufficient to change the meta tags and some content for them to be seen as separate sites and not duplicates?

We have gone through and setup separate my business pages etc.