Move labeled subset of Gmail messages to another account

I want to move my messages from one Gmail account to another, but not all and that is the problem. All manuals in the web shows how to set up forwarding/import that moves all messages, but I don't want to do that, I want to move messages by some label.

I tried email import feature making target messages unread beforehand, but anyway it imported all mailbox, both read and unread.

Is there a way to more fine-grained import?

Thanks.