Upgrade from Jira 6 to Jira 7.11 - jira.extension.container.provider deprecation

We have some core classes override for UserSearchService using “jira.extension.container.provider” property (picocontainer override). In the latest version of Jira (7.11.1) this functionality for overriding core classes has been deprecated and we need to override the Core functionality in order to hide the user mentions in every Jira field (mention fields, User pickers…) based on some custom criteria.

Do you know if there is a way of restricting that searching or by filtering the Core results?