The biggest problem I think is that people feel that any potential trading partner might not be on the same server as they are. To overcome this problem you'll need to make sure that there are enough people from your server in the group.
To ensure this you will have to search people on your server (players you can see in Transfer Market,Negotiations,Cup,Champions League in the game) on facebook and add them to the group. Now this will include sending messages and requests to strangers but I think in due course of time this will benefit everyone. Because everyone needs to buy and sell players in this game. Token buyers might argue that they don't need negotiations to buy any player but to sell off their old players they'll also agree that negotiations are better than selling players in the transfer market.
I have a way easier way/approach : just take a look at the teams/squads of you're opposition in the league/cl or cup and make a offer or two on the players you like. 100% guarantee you're on the same server!
Then again, offers no guaranteed
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