The great psychologist Eric Berne believed that in order for humans to acheive autonomy, they should divorce their parents at the earliest opportunity and keep them at a reasonable distance there after. Visting them only on occasion afterwards. My own personal experience tells me he is not wrong, and that same should apply to your siblings.
My own animosity with my bother is testimony that inter family rivalleries can not only be detremental to health, and it get also get downright dangerous. Having said that, i get on much better with my sisters, however I only see them about twice a year as they live far away from where I am.
Any opinions ?
Ian