You can make life easier by creating several raid arrays on the same disks and tie them together with LVM.
For example split your three 160GB drives into 4 partitions each and create a raid over the three disks.
sda -> sda1+sda2+sda3+sda4, etc. md0 = sda1+sdb1+sdc1, md1=sda2+sdb2+sdc2, etc.