Groupware are computer-based systems designed to support groups of people working together providing a shared environment. Given that developing this kind of application is not a trivial task because of the huge amount of time wasted on implementing infrastructure aspects, a few component-based approaches appeared. Groupware Workbench structures groupware using components and tools that encapsulate the technical difficulties of distributed and multi-user systems based on the 3C Collaboration Model. In this paper we propose the development of a Collablet product line using the Groupware Workbench. This approach combines the benefits of Software Product Lines and software components providing a systematic way for tailoring customized groupware through the use of Collablets automatically derived from product lines.