thanks for your reply. As far as I understand, it isn't possible for an airline to be a direct member of multiple alliances.
On the wikipedia page of Oneworld, there is an table with all members of Oneworld.
http://en.wikipedia.org/wiki/Oneworld
Here you see member airlines, but also
member affiliates and
non-member affiliates.
As far as I understand, all these airlines in all columns, are part of the Oneworld network.
Is it possible for an airline in the second or third column to be part of multiple alliance networks?