Trilingualism in children

I've read that for the development of bilingualism, one of the parents can speak to the child exclusively in language 1 and the other speaks exclusively in language 2. This is supposed to keep the child from falling behind in either of the two languages.

Now, let's say I was to have a child. I'm trilingual and I want to pass on all three languages onto my child. My question is, how would I keep the child from combining the languages into a hybrid language?

If it's important, the languages in question are English, Russian, and Mandarin.