Configure Multi Project Customfield
This how to article will explain how to limit the selectable projects when any Jira user is editing the custom-field value.
Instructions
To configure a custom field
Go to Customfield Admin Page
Find the Project Picker (multiple projects) custom field created in step 1 and click on ( ... ) > Contexts and default value
At the bottom of the page click on Edit custom field config
The configuration page will load
5. Choose the desired projects
6. Click Save
The admin user is able to select only one method of limiting Jira project visibility:
By Project
By Project Category
By Project Type