nbu 7.5 os is solaris

Ihave a query regarding a restore.

My backup is on tape.I require 5 media for restore.media are not in library.We have 5 library in one domain.we have 4 robot control host.

I need to ask on site team to insert the medias .when i goes in media section and search the media it says it is none and robot control host is not shown.

To which robot control hosts this media be inserted?(i mean to which library)

nbu 7.5.0,.4

solaris