POP Chain - trying to pop all emails including poped ones

POP Chain - trying to pop all emails including poped ones

I have the next problem.

I have main Zoho account (A) which pops from other 2 Zoho accounts (B,C) successfully.
Then I have a Gmail account which pops from my main Zoho account (A).
My Gmail account succeed to pop only A emails, but not B,C emails (they keep staying in Zoho A).

Any way to make gmail account to pop also B,C emails ?

Thanks,
Gil.