Adding voice to staff causes VST selection different from initial voice

Is there a way, when adding a voice to a line, to have that new voice use the same instrument setup as the first voice? Example: I write a lot of SATB and Organ music (new and arranged) and right now I’m using Garritan CPO library for the organ part because of its flexibility. When I add a second voice to, for example, an organ staff, Dorico chooses the Halion VST and its organ (full organ) instrument rather than using the Aria VST that the initial voice uses.