Isolated systems and resource production Q

[AMF]

If a system is isolated from the rest of my empire by the closing of a warp point, assuming it has space ports and satisfies all other normal resource acess criteria, do it's resources still get to my empire

- If there is a friendly empire in between me and the isolated system?

- If there is a hostile empire in between me and the isolated system?

And, if the answer is NO to the above, will getting a single planet in the intervening system controlled by the other empire alleviate this problem?

Thanks,

Alarik