Yes, as long as you have all the documentation and status of the cargo, you can decide who takes care of your import export. Also, it is possible to have more than one customs brokers and work with them, however, there should be convincing reason behind it, as all international customs brokers are certified to take care of all aspect of the project, using two or more customs brokers or brokerages, increases the risk of inconsistent Customs declarations, cost, hourly work and results in more work. Instead of spending time with 2 or more customs brokers in West Island, spend the time to find the right customs broker at the first place!.