Derivative or sub-translation

**Is your feature request related to a problem? Please describe.**
We have a project where we sometimes create derivative installations that require slightly different wordings for some translations (e.g. "Group" is known as "Community").

**Describe the solution you'd like**
I'd like to have some way, either a sub-project or a sub-language that can selectively translate some strings and use another translation/project for all other strings.

**Describe alternatives you've considered**
Found nothing that was easy so far. Re-importing another translation could work but it could overwrite customisations that have been made.