First idea is I would reject the idea of trying to share handles with a single daemon - why not clone the daemons instead and have a transaction monitoring layer that sorts out which daemons are busy or not - keep a stock of so many available daemons of a particular kind (say 8) that have completed initiation but are not yet servicing requests, so that if two are busy handling requests, a ninth and tenth start initiating so that the stock control count of 8 identical daemons (for example) is always ready to handle new requests that are not yet received. When more than the required stock of clones is ready for new requests, kill off the excess to control their number. The transaction monitoring layer needs to identify requesters and keep a table of which cloned processes are allocated which requests and which are free.

Update: I have wound backward my thinking to the functional design stage which I myself tend to want to be in a feasible state before I feel safe in suggesting a choice in regard to such clones being independent processes, forks, threads or POes.