Since Release ND6, if you have more than 50 rooms, only 50 will appear when a user tries to schedule a room.
You can increase that limit, but remember two things:
- Modifications to the standard mail template are not supported by Lotus Technical Support,
- Currently, there is no known limit as to the number of rooms the display can be set to.
Detailed information, including steps to change the default, can be found in this technote:
Title: Can You Control the Results From the Scheduler Action Button in the R5 Invitation Form?