If an integration is in a Project, one or more environments may be specified for the integration and that integration is available to resources that are part of the pipeline sources that share at least one of those environments. By default, integrations are in the DEV environment.
Integrations that are not in any project may only be used by pipeline sources that are not in a project. By default, these integrations are available to resources in all pipeline sources that are not in a project.
You can establish those usage restrictions when you add or modify an integration.
Uncheck the option to Any Pipeline Source.
In the revealed interface, select from the list of available pipeline sources and move the row(s) (by click-and-drag or arrow button) to the list of included pipeline sources.
When finished, click Create (if adding an integration) or Save (if editing).