Only working my way through the players book at the moment but one thing came to mind.
Dwarves and elves "tolerate" each other and I guess halflings go along with everyone somewhat but other than that they all seem to hate each others guts out.
I can appreciate there is the odd character or situation where the players wont get along, but in this setting it seems nearly impossible to explain why a group would at all choose to stay together, help out or consider each other "friends" unless they spawn from the same race.
How do you evade this issue, have you toned down the hatred the races feel for each other or are you tying the characters together through some exceptional backstory/event?