how to hide a sensitive workbook while users are still able to enter onto it

hello,

quite a difficult question to get my head round.

we have a spreadsheet called prop reg (proposal register). as business is picking up and staff numbers increase it's no longer appropriate for information regarding our finances to be exposed to everyone.

this proposal register needs to essentially be blocked from 'regular' staff view, however with the ability for them to be able to enter information on to it.

in my mind i would see that this would work with some sort of switchboard system where (when they open the spreadsheet) they would be greated with a 'ENTER NEW CLIENT' form.

however:

a) how do i create this so the data on the spreadsheet isn't visible.
b) how do i make it available for the directors to access the spreadsheet with full permissions.


i have attached an example spreadsheet to hopefully shed some light on exactly what i need. The first 5 columns would be entered by the 'staff' and the commission paid fields would be completed by someone who had full access.

many thanks