Search for tags RG


I am creating a news site. The news have tags (for example Sports, Fashion etc). The tags are their own data type with only a text field. The news data type has different fields but one for tags (list of tags). So that is how the connection is made between the news item and the tag. I am trying to filter a RG with related news and I want the search to be constrained by only showing other news with at least one of the tags on current page news tag. So one news item can have multiple tags, but I want to show all news items with at least one of the tags equals one tag of current page news. How do I do this?

Sorry for a confusing explanation, I hope you understand and can help me.