Aldryami, Mostali and Uz will not get along.
But if you play in a more generic fantasy setting there can be ways to have all three races in one group.
1) Maybe there this is a anti racist group, working together against the anti-human human society of the world.
Starting scenario: This is a world of humans. The thinly spread non-humans are disliked, but searching each others company, even if they don´t like each other either, to have a stronger point against the anti-human racists.
2) Maybe they all belong to the same religion. An elf cult, a dwarven cult, and a troll cult... each seperate, but worshipping the same deity. Now these individuals follow the way of their god... and ignoring the races of the others, for the common good of their religion.
3) Maybe they are all outcasts of their societies. Nobody wants them, and they are the only ones to accept each other, because it is better being acompanied by other outcasts than being on your own.
4) Maybe they are under contract by someone, and are forced by this contract to work with each other.
5) Maybe they have all the same enemy, and band together in order to beat him.
etc.