I do not think we have ""OR"" operation for tag filter.
However, one way by which we can achieve this is by creating tags that allow us to get the desired results with filtering options provided.
For example, If an item is Employee type, Tag that item as; Employee-Not Contractor-Not Ex-Employee, and so on.
Thus, you will have the exact tag value known which could help you filter using +, - and ; options.
This may not be the best solution and others can pitch in, but I believe it's simple to implement.