Actual Status:
LLD on Windows machines can only be filtered by file system type (NTFS, FAT32, etc). On a setting where two servers are monitored by LLDs and both have mounted drives from the other server, this will led to double checked file systems.

Target State:
Additional LLD macro #DRTYPE which will provide drive type information by MSDN function GetDriveType(lpRootPathName). By defining the LLD rule with this macro and filtering by, for example, the return code DRIVE_FIXED it can be secured that only internal drives like C:\ will be checked.
From MSDN this function returns the following:
Return code/value Description

DRIVE_UNKNOWN 0 The drive type cannot be determined.

DRIVE_NO_ROOT_DIR 1 The root path is invalid; for example, there is no volume mounted at the specified path.

DRIVE_REMOVABLE 2 The drive has removable media; for example, a floppy drive, thumb drive, or flash card reader.

DRIVE_FIXED 3 The drive has fixed media; for example, a hard disk drive or flash drive.

DRIVE_REMOTE 4 The drive is a remote (network) drive.

DRIVE_CDROM 5 The drive is a CD-ROM drive.

DRIVE_RAMDISK 6 The drive is a RAM disk.

This functionality can be implemented by applying the attached patch.

For the future the functionality of this and other macros can be expanded by implementing a multiple macro filtering.