How can I set priority to multiple series entry rules?

I want to create two different entry rules for a series and ensure that a user can only meet the conditions for one of those rules. That is because I want to A/B test a series start message, and all series begin with entry rules.

Here are limitations relevant to what I'm trying to do:

1) Split tests can't be used to begin a series

2) Only users who meet certain conditions are eligible to receive the B version of the message, so these conditions have to be factored into one of the entry rule blocks

3) All Intercom objects (tags, rules, split tests, etc.) between an initial entry rule and the first message sent introduce wait time before the first message is displayed for a user

In the form of a question: how can I set some kind of priority to entry rules, such that Intercom first looks at Entry Rule Block 1, and if a user meets those conditions, the user begins the series there, and the user is not checked against Entry Rule Block 2?

Or, is there some other way of ensuring that a user can't meet multiple entry rules inside of a single series?

Thanks for your help!