Perhaps Kasia should be offered a way to participate in core business projects, or a raise, or both. Seems only fair after such praise from colleagues and HN.
Also, she already does participate in core activities. It would be much easier for us to deal with losing a couple of our best engineers than losing Kasia. Which is also a response to some voices in the discussion downplaying the value of the "office manager's" job. I partially blame common perceptions of this job being "just a secretary to everyone," which could be farther from what we have.