when configuring blocking notifications i want to allow it for some users and for the users who dont have access show a block notifications
Block notification can seen only if the transactions is blocked, Block/ allow depends on the access policies, threat protection or data leak prevention policies.
So there is no way where we can show block notifications based on access policies?
No. The action of blocking is already based on access policy. What I think you are asking is: Can you send block notifications based on access policies, or in the specific case you asked about, send a user notification based on username or user group? The answer to this at this time is no.
If you can provide the community with a use case, we might be able to find another method or there may already be an enhancement request that matches your use case. What comes to mind for me is: A contractor and an employee access a web site, or encounter a threat and while you want the employee to receive the standard company block notification, you prefer that the contractor not receive the company-branded message and instead receive no notification (but you still want the site or threat blocked).
Is that example in any way similar to your use case?