Which series is activated for a user who satisfies the criteria for more than one series?

I have set up series to send out a post to users, and I observed there could be users who are eligible to be a part of multiple series. Which message will they get first?

Since it is an in-app post on the same page of our product, I am a bit confused about what entry rules to add.

I have used multiple AND's and OR's on Series started, disengaged, completed, etc. as an entry rule to make sure the message that is relevant goes first. Just wanted to confirm on this.

Any help is appreciated.

Thanks in advance!