[{"_id":1,Title:"title1",IsHomePage:true,IsTagged:true},{"_id":2,Title:"title2",IsHomePage:true,IsTagged:true},{"_id":3,Title:"title3",IsHomePage:false,IsTagged:true},{"_id":4,Title:"title4",IsHomePage:false,IsTagged:true},{"_id":5,Title:"title5",IsHomePage:false,IsTagged:true},{"_id":6,Title:"title6",IsHomePage:false,IsTagged:true},{"_id":7,Title:"title7",IsHomePage:false,IsTagged:true},{"_id":8,Title:"title8",IsHomePage:false,IsTagged:true},{"_id":9,Title:"title9",IsHomePage:false,IsTagged:true},{"_id":10,Title:"title10",IsHomePage:false,IsTagged:true}]

db.collection.aggregate([{"$match":{IsHomePage:true}},{"$unionWith":{"coll":"collection","pipeline":[{"$match":{IsHomePage:{$ne:true},IsTagged:true}},{"$sample":{"size":5}}]}}])