[{startTime:"08:00",endTime:"09:00",id:1},{startTime:"08:10",endTime:"09:00",id:2},{startTime:"08:20",endTime:"09:00",id:3},{startTime:"10:00",endTime:"11:00",id:4},{startTime:"10:20",endTime:"10:50",id:5},{startTime:"11:30",endTime:"11:40",id:6}]

db.collection.aggregate([{$match:{}},{$setWindowFields:{partitionBy:"",sortBy:{startTime:1},output:{previous_endTime:{$shift:{output:"$endTime",by:-1,default:"Not available"}}}}},{$set:{c:{$cond:{if:{$and:[{$gte:["$previous_endTime","$endTime"]},{$gte:["$previous_endTime","$startTime"]}]},then:0,else:1}}}},{$setWindowFields:{partitionBy:"",sortBy:{startTime:1},output:{c:{$sum:"$c",window:{documents:["unbounded","current"]}}}}},{$group:{_id:"$c",c:{$sum:1},id_List:{$push:"$id"}}},{$match:{c:{$gt:1}}}])