Dunno if it's possible, but in my family - in America - we have trusts set up for what will happen to my father's estate in the event of his death. It's basically a means to minimise inheritance tax.
There's no obligation to split things 50-50 between siblings. In fact, there's no legal obligation to bequeath one's offspring anything at all. As far as a 'battle', that's entirely dependent on how well the estate is set up.
With a trust, a trust can be incorporated, like a business (at least, it can and was in my dad's domicile state, Texas), so it's actually the business trust that inherits, rather than an individual - although individuals can act on behalf of the trust: buying and selling things, drawing income from the trust, etc.
Could be a way round any sticky issues.