How do I reconcile mutually exclusive skills and maximum assignees per story?

[Kevin Teich]

We're a game development team, and our skills are largely exclusive, like "Design", "Engineering", "Art". Each team member has only one of those skils. Most of my stories require at least one of those skills, but to get Portfolio to assign multiple people to a story, I need to set the "Maximum assignees per story" to 3. Now, if I have a story that requires 2d Art and 3d Engineering, Portfolio will correctly assign an artist and an engineer to that story in the same sprint. That's great! But what it also will do is try to assign multiple people of the same skill; in the example above, it might try to assign one artists and two engineers, and I only want one engineer to be assigned to it. Is there a way to limit the number of assignees in the same skill to a story, but still have multiple assignees to it?

I don't see an option so I feel like this is more of a workflow thing. Is there a better setup I should consider?