Authorisation in sales order

Dear all,

Just want your views on the feasibility of the following :

I want in my sales order for a particular company code, that authorisation for making changes should rest with only few people. For eg. if finance people have created the pricing and condition types in a sales order then sales people should not be able to change that.So my question is:

Is it possible in a sales order to grant authorisation to make changes at the

-Order Level

-Individual field level.

regards

Sapshed