A nation can only belong to one faction.  
Only puppets come with you if you switch factions.

R5: I made a faction with Hungary through focus tree, then did Germany alliance too, so it kicked me out of the one with Hungary? Why does the game not just make a big one? Is this in every tree?

&amp;#x200B;

https://preview.redd.it/mcv94am630781.png?width=1582&amp;format=png&amp;auto=webp&amp;s=edab50012856f387e6c17175907fc8a110fce576

I made a faction with Hungary through focus tree, then did Germany alliance too, so it kicked me out of the one with Hungary? Why does the game not just make a big one? Is this in every tree?

Why?