How to deny access for a certain user to a certain infoblock element?

Question

1C-Bitrix

Hello!
How can I disable access to an infoblock element?
There are users (user1, user2, user3), infoblocks (infoblock1, infoblock2).
Infoblock1 as a section for infoblock2. When user1 adds infoblock2 element he should select only the first element of infoblock1, and user2 adds infoblock2 element he should select only the second element of infoblock1.
How can you do?