[otrs] Customer notification on follow up

Hello, is it possible to receive notification for Customer via e-mail (Outlook) on follow up? In case this Customer is tracking tickets of several companies, not only tickets created by himself. All the tickets are visible for him via Customer interface, but to make it more convenient Customer is asking to send e-mail if there is an answer to any of existing tickets to force him to log in via Customer interface only for significant reason and not to log in many times hoping for an answer. thank you in advance, Matas