Guys,

If I change this "Indeed it is technically impossible." to "Indeed it is with the current setup technically impossible.

And yes one of the issues is the database.

This is an example, not my real data.

EU database:
ID = 55555555555
EMAIL LOGIN = whitewolf@email.be
FACEBOOK LOGIN = whitewolf
GMAIL LOGIN = whitewolf@gmail.com
CHAR1 = White Wolfs
CHAR2 = White Wolfs B
CHAR3 = White Wolfs FW
CHAR4 = ...

I also have on RU

RU database.
ID = 111111111111
EMAIL LOGIN = whitewolf@email.be
FACEBOOK LOGIN = whitewolf
GMAIL LOGIN = whitewolf@gmail.com
CHAR1 = White Wolfs I
CHAR2 = White Wolfs B
CHAR3 = White Wolfs FW
CHAR4 = ...

Merge database = to many conflicts.

Then undo the merge