Large displays have been used in meeting and workspace environments over the last couple of decades. Traditionally, meetings have operated in a one-operator-per-display paradigm where a single user physically connects his/her computer to the large screen display to make it visible to other meeting participants. While this approach works well for some types of meetings (e.g., presentations with a single presenter), a more flexible system is required to support a wider variety of collaboration patterns. In particular, current tools offer poor support for meetings with multiple presenters. LACOME aims to solve this problem by providing a better ad hoc collaborative meeting environment. LACOME was originally designed and developed at The University of British Columbia; we extend the system to consider privacy and security concerns. We conducted a series of focus groups to obtain feedback on the initial design of the system. We implemented new features that provide enhanced awareness of users' shared workspaces. We also developed an access control framework in the system that allows users to assign permissions on an ad-hoc basis. We undertook an initial evaluation of the LACOME system.