Project managers often have to share resources (people, tools and facilities) with other project managers. It is important to have a system to schedule these shared resources, as well as to communicate the schedule to the organization.
Often there are different tools that need to be used for each type of resource. Decide how these resources will be scheduled (Project Server, Databases, Spreadsheets, etc.) and communicate these methods and results to the team.
If possible, meet with the owners of the shared resources often to make sure the plan is still solid and no adjustments need to be made.