Currently, it is implied through the following text regarding the purpose of arbiters to only break ties.

https://docs.mongodb.com/manual/tutorial/add-replica-set-arbiter/

Arbiters are mongod instances that are part of a replica set but do not hold data. Arbiters participate in elections in order to break ties. If a replica set has an even number of members, add an arbiter.

Multiple arbiters are usually against best practices and I recommend calling that scenario out explicitly.