As stated there, the comma is a
union operator, so you can't allow a group to target others in the group but not themselves. You're proposing the addition of an
intersection operator. But again, it would require creating a
parser with associated grammar and order of operations (in other words, way too much overhead for this feature).
Why is a parser required? Well, what does #admin,#operator+^ mean? Does it allow the targeting of admins and yourself as long as you're an operator, or does it allow the targeting of yourself as long as you're an admin or an operator? Parsers are responsible for resolving these ambiguities.
