I don't think it is possible. One partition can only be mounted to one directory. But one directory and its sub-dir can mount on several partitions. For example,
we can do this,
mount /dev/sda1 /
mount /dev/sdb1 /usr
mount /dev/sdb2 /usr/database
mount /dev/sdb3 /usr/programs
mount /dev/sdb4 /usr/other_programs
mount /dev/sdc8 /usr/programs/eddie
etc....
but we can not do following,
mount /dev/sda1 /
mount /dev/sda2 /
nor,
mount /dev/sdb2 /usr/database
mount /dev/sdb2 /usr/programs
You perhaps have allocated too much space to a partition, right? So you may have to re-partition the disk.