possible to setup multi master with multi slave with galera with mariadb?

[et4...@gmail.com]

recently, I learned how to use galera and setup master to master replication with mariadb but I am wondering if I can also use galera with some setting adjustment to have multi master and multi slave

let's say right now I have two master, I want I want to create two slave as back up in case of anything happened to both master.

I followed this tutorial to setup multi master replication https://www.howtoforge.com/tutorial/how-to-install-and-configure-galera-cluster-on-ubuntu-1604/

I was reading this post https://clanxii.altervista.org/blog/configure-mariadb-maxscale-master-slave-galera-cluster/ but it needs another server to do the proxy so I haven't give it a try yet if there is a better way

I thought of making all 4 master but then I realized if I do that, the increment offset would be totally off since the other two will never be used

Does anyone have an idea how this can be done?

Thanks in advance for any suggestions