You're going to need more detail than that. JQL will let you filter on "Project = 'something'" or "Project in (project1, project2, project3)". I would start by using the Filters->Advanced Issue Search view. On the right of the search bar is a "Switch to basic" - start with that, and get your query roughly right, and then "Switch to JQL" and add any missing options you think you need.
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