How can I separate Available and On Hand inventory tabs?

[MHales]

Hi - how can I seperate / unlink the Available and On Hand tabs in inventory? I am wanting to have say 10 items on hand (actual stock) but keep a reduced Available number for actual sale.  Currently they adjust to the same number which seems pointless having 2 tabs or am I missing something. I need to be able to send a monthly on hand report to my accountant for tracking... Thanks in advance for any help.