How to make string divisi in BBC Core Orchestra

I am still relatively new to Dorico, and I am still learning. I am trying to make more use of the BBC Core Orchestra, but I am disappointed that I cannot make string divisis on the same staff like I can with the default Halion Pro orchestra. Unless there is a way to activate that? If someone has a suggestion, I would appreciate the advice.

The choice of sample library shouldn’t affect whether you can create a Divisi or not.
However, divisi can only be made on Section Players, not Single Players. (Similarly, Single Players can hold more than instrument, but Section Players can’t.)

Section Players have ‘two heads’ on their icon, as here:

Screenshot

True, but the section violins of BBC Core do not divisi.

I don’t think that at the moment there’s a way to control whether you have a full section playing as play-back or half a section when divisi are involved. In a DAW, you would input your music on separate tracks that generate different sound sources. Dorico should have a way to tell the vsti “now I want 6 players only” (or 4, or 3, or 2, depending on the size of your virtual orchestra and the section involved) but I don’t think there’s a satisfying solution yet.
Spitfire’s BBCSO is quite limited in the choices you have, even in the Professional tier. And I find it especially slow and heavy to work with, so it’s definitely become my last choice… (and unfortunately one of the first I invested in)

My impressions echo yours. The Spitfire Albion strings do divisis well but have no proper expression maps. What do you think of the VSL libraries? The Synchron Prime looks interesting.

The BBC orchestra has performance issues (unfortunately rather more in Dorico 4 than 3.5 on my system for some reason) but they can be reduced by hosting under Vienna Ensemble Pro. It is buggy and not that easy to work with but the results can be exhilarating in the right sort of music.

VSL is a safer bet overall and fairly easy to programme the EM’s for though for full orchestra, I don’t find the starter versions the most involving. I already have several volumes of the Special Edition so the Prime is of no interest but can be probably safely recommended if you like the sound (and are not annoyed by the absence of trills --what are they thinking of…)