When tagging an internal search engine, you can use any character you want to separate keywords.
There is no way for hits containing multiple keywords to be split up, and as such any results containing several entries will be displayed in the interface as you sent them.
You are free to send such keyword information as:
- Keyword A - Keyword B
- Keyword A | Keyword B
- Keyword A _ Keyword B
However, this is also how that information will appear once it has been processed. Filters will still work, such as a "Contains - Keyword B". To separate this data into individual keywords, reprocessing in an external tool will be necessary.