—If God is all-knowing (and He is), then He can’t know a group (like the Church) and not know its members. If He doesn’t know its members, then He is not all-knowing.
He IS all-knowing, so He does know its individual members.—
He is all knowing and knows who is going to choose to become members, but He doesn’t choose for them to be members. He has a chore and a idea of what He wants the general church to accomplish. That is what he is “predestined”. I am not saying He doesn’t know who will be in His church. I am saying he hasn’t predestined specific people to be in it.
The following 2 verses says He does predestine individuals. Groups aren’t called and justified, individuals are. And, it is definitely individuals who are adopted.
Romans 8:30 And those he predestined, he also called; those he called, he also justified; those he justified, he also glorified.
Ephesians 1:5 he predestined us to be adopted as his sons through Jesus Christ, in accordance with his pleasure and will—