[keycloak-user] Users to group mapping

Our login times are not acceptable with keycloak since during the login keycloak is doing the users to the group mapping. Is there any way we can seperate the two concerns of logging in (validating the password vs this group mapping). Is there a way to schedule this users to group mapping in the background after the login is finished ? Any input is appreciated , since we do have large groups which the users belong too and the performance is painfully bad. Shweta