hello again!!

I'm starting to get the feeling of GTD and I'm becoming addicted haha
another question please:

I'm managing 3 companies (small companies) from the same office, and like most of us now I'm there 90% of my working time, where I have computer, internet, phone, etc.

do you think is good idea to make context for each company?, maybe is not really a context per se, but I feel (and that's why I think this is a mistake, GTD is changing everything I "felt" was a good way of organizing for something that is much better) that is important to separate this tasks/actions/projects.
can you please tell me about this from your experience?

thanks in advance!!