I don't think they can be kept together. I don't know for sure, but I'm thinking in the end you'd end up with one fat happy vinegaroon instead of two. My specimen isn't super aggressive, even to prey, but I don't think it's worth the risk.
Pretty sure they'll kill each other, unless they are a sexed pair, though even then after a while the female would probably eat the male. It's best to keep them separately, they are not at all like their communal relatives the Amblypygids, (whipspiders).