Unfortunately not, and it seems like a quality of life oversight to me not to be able to select.

Honestly, given the length of early access (and the fact that this isn’t a new complaint) I wonder if it’s actually a choice rather than an oversight. My hope would be that it’s not difficult to implement, and can be modded in now and added to the game later. Fingers crossed it’s not due to a technical limitation

The devs did mention in the weeks before launch that it was something that they wanted to address but that it was very difficult to implement with their current system and how the conversation cutscenes work. They did try different things internally that they never added to Early Access but they weren’t happy with any of their solutions and so they opted to focus the efforts on polishing other aspects of the game.

I have a very limited understanding of have development, but isn’t it as easy as checking which characters/players are currently participating in a conversation, be it actively or just listening, and then allowing the player(s) to choose a characters stat for a given skill check?

It might have to be limited to stuff like investigating, arcana checks, athletics checks, etc. and not include conversation relevant checks, like intimidation, persuasion, and deception