I have 4 LTO Drive and 2 DLT in the same physical STK L700 Library. But I
have define 2 Virtual Lib
Here is my config file :
Try to not used the "Shared=Yes", when used you cannot remove without
deleting the library.

/* Device Configuration */
DEFINE DEVCLASS DBFILE DEVTYPE=FILE FORMAT=DRIVE MAXCAPACITY=16777216K
MOUNTLIMIT=1 DIRECTORY="F:\IMPORT" SHARED=NO
DEFINE DEVCLASS DLT7000 DEVTYPE=DLT FORMAT=DLT35C ESTCAPACITY=73400320K
MOUNTLIMIT=DRIVES MOUNTWAIT=60 MOUNTRETENTION=15 PREFIX=ADSM LIBRARY=STKL700
DEFINE DEVCLASS DLTHP DEVTYPE=DLT FORMAT=DLT35C MOUNTLIMIT=DRIVES
MOUNTWAIT=60 MOUNTRETENTION=60 PREFIX=ADSM LIBRARY=HPDLT
DEFINE DEVCLASS EXPORT DEVTYPE=FILE FORMAT=DRIVE MAXCAPACITY=655360K
MOUNTLIMIT=1 DIRECTORY="F:\IMPORT" SHARED=NO
DEFINE DEVCLASS LTO DEVTYPE=LTO FORMAT=ULTRIUMC ESTCAPACITY=209715200K
MOUNTLIMIT=DRIVES MOUNTWAIT=60 MOUNTRETENTION=15 PREFIX=ADSM
LIBRARY=STKL700LTO
SET SERVERNAME FRBUCBKP02MEDGE_SERVER1
DEFINE LIBRARY HPDLT LIBTYPE=MANUAL
DEFINE LIBRARY STKL700 LIBTYPE=SCSI DEVICE=LB6.0.0.7 SHARED=YES
DEFINE LIBRARY STKL700LTO LIBTYPE=SCSI DEVICE=LB6.0.0.7 SHARED=YES
DEFINE DRIVE STKL700 DLT4 DEVICE=MT4.0.0.6 ELEMENT=504 ONLINE=Yes
DEFINE DRIVE STKL700 DLT5 DEVICE=MT5.0.0.7 ELEMENT=505 ONLINE=Yes
DEFINE DRIVE STKL700LTO LTO0 DEVICE=MT0.0.0.2 ELEMENT=500 ONLINE=Yes
DEFINE DRIVE STKL700LTO LTO1 DEVICE=MT1.0.0.3 ELEMENT=501 ONLINE=Yes
DEFINE DRIVE STKL700LTO LTO2 DEVICE=MT2.0.0.4 ELEMENT=502 ONLINE=Yes
DEFINE DRIVE STKL700LTO LTO3 DEVICE=MT3.0.0.5 ELEMENT=503 ONLINE=Yes

Hope this help.