You're speaking about the 'sphere of compassion', I'd say there are two factors at play. There's 'how large' the in-group is (where we could say someone who cares for all animals is more compassionate than someone who cares for all human beings) and 'how intensely' people feel compassion for their in-group (which is harder to quantify, but still a real phenomenon).
edit: Compassion for one's in-group can be very real, even if the in-group is small. It's almost like a breadth-vs-depth question. I've even heard of some studies suggesting that having very intense feelings of compassion for one's in-group is predictive of callousness towards the out-group.
I actually don't believe it's possible to, in any meaningful way, perceive and vicariously experience the emotions of others and to continue to carry any deep hostility, or to do so and not feel some degree of compassion.
Sociopaths score low in empathy but are excellent at perceiving others' emotions.
edit: Compassion for one's in-group can be very real, even if the in-group is small. It's almost like a breadth-vs-depth question. I've even heard of some studies suggesting that having very intense feelings of compassion for one's in-group is predictive of callousness towards the out-group.