The optics in the receiver cabin, in its present as well as in its future layout, allows simultaneous observations with up to 4 heterodyne receivers. Table 1 lists the combinations expected to be available next winter. A100 and A230 refer to the new generation receivers centered at 100 and 230 GHz, respectively, and housed in Dewar A which is served in reflection by the future beam divider. The new generation receivers B100 and B230 are planned to be available as a backup. The 2MM and 0.8MM receivers refer to the same SIS receivers as installed last winter.