word request - How do you say "which each" or "who each"?

I speak in Persian, sometimes as I translate a sentence from my native language to English, I doubt if its structure is correct.

I want to say (for example)

"I have some children who each have a responsibility".

"There are some objects which each does something"..

Are they grammatical sentences? what should I say instead?

Answer

Both who each and which each are acceptable, though be wary of verb agreement:

I met three sisters who each have identical twins.

The substance is regulated by the US and the EU, which each specify different toxicity levels.

In this case, we require plural agreement, …objects which each do something to be grammatical.

As Kevin notes, however, this construction may sound awkward; rephrasing your examples to say each of whom and each of which would be more natural. In that case the verb is singular for example "there are some objects each of which does..."