I'm writing a proposal for work. For it, I would like a word that describes the concept of brain drain - lots of people leaving the country and taking their knowledge with them - but that is limited to within the same company.

Wikipedia (and others) [defines brain drain as](http://en.wikipedia.org/wiki/Brain_drain):

> 
> ...the large-scale emigration of a large group of individuals with technical skills or knowledge.
> 
> 
> 

What I'm looking to describe, however, is a situation where one or two very knowledgeable people change jobs, switch departments, or leave the company (not necessarily leaving the country) without imparting that knowledge to others. Is brain drain the best fit or are there better words?