Two Separate Sites One User Table

[SelamT]

Hello,

Is there an easy way to prevent creating separate memberships on two different websites using the user table of only one of them?
Everything else can be separate, but when a membership is opened on one site, the same information should be added to the other site's database. Is this possible?

Thanks,
Two Separate Sites One User Table

free plugins
minecraft paid for free
mcmarket
mc-market
free minecraft paid plugins
free minecraft plugins
spigotmc
SpigotMC
aac free
ewg free
Minecraft Premium Plugins
ewg free download
litebans free
epicworldgenerator free
free schematics
leaked schematics minecraft
schematics
schematics leaked
schematics free
minecraft schematics free
paid minecraft schematics free
paid minecraft schematics for free
free cracked plugins
free cracked minecraft plugins
plugins
featherboard download
featherboard plugin download
antiaura download
xenforo leaked
xenforo for free
xenforo addons