how to define a trigger in a mongoose schema

is there any kind of trigger at mongoose model level which provide the capability to set the value of the open field = false when the number of the members collection reaches 100?

var mongoose  = require('mongoose');
var Schema    = mongoose.Schema;

var listSchema = new Schema({
  name: {
    type: String,
    required: true,
    trim: true
  },
  desc: {
    type: String
  },
  open: {
    type: Boolean,
    default: true
  },
  members: [{
    userid: {
      type: Schema.Types.ObjectId, ref: 'User'
    },
    prId: {
      type: Schema.Types.ObjectId, ref: 'PR'
    },
    checkedIn: {
      type: Boolean
    }
  }]
});

module.exports = mongoose.model('List', listSchema);