Dynamic Order Status Column Function

I am looking for assistance coming up with a function (or maybe not a function if there is a better way) to make the Status column in my order table dynamic. The default value for new records will always be "1" to designate a quote. At this point the field is not dynamic. Once the customer confirms the order, the user needs to execute a command to change the status to "3" to designate a Confirmed order. At this point the field needs to be dynamic based on the shipping records. There are two order details tables. One for sales items and one for rental items. Each of these details tables has their own shipping record. the CheckInOut Tables are for rental while the Ship tables are for sales. So, if some (but not all) of the items in either of these order details tables has a shipping record associated with it, then the status should be changed to "5". If everything has been shipping, the status is changed to "4". If everything has been shipping but some items have been returned, the status is "6" if everything has been shipping and all of the RentalDetail items have been returned then the status is "7" and if there is any other combination of a variety of ships and returns, the status is "8". Also, at any time, the user needs to be able to execute a command to change the value to "2". once the value is changed to "2" the field stops being dynamic again.

Below are my tables creation commands.


CREATE TABLE OrderHeader
(
OrderID int identity primary key,
Status int,
StartDate datetime,
EndDate datetime
)--Use Type 1 = "Quote" Type 2 = "Cancelled" Type 3 = "Confirmed", Type 4 = "Shipped", Type 5 = "Part Shipped", Type 6 = "Part Returned", Type 7 = "Returned, Type 8 = "Mixed"
CREATE TABLE OrderRentalDetail
(
OrderRentalDetailID int identity primary key,
OrderID int FOREIGN KEY REFERENCES OrderHeader(OrderID),
ItemName varchar(30),
Qty int,
SiteID int,
)
CREATE TABLE CheckInOutHeader
(
CheckInOutID int identity primary key,
Type int,
SiteID int,
ActionDate datetime
)--Use Type 1 = "Ship" Type 2 = "Return" Type 3 = "Lost"
CREATE TABLE CheckInOutDetail
(
CheckInOutDetailID int identity primary key,
CheckInOutID int NOT NULL FOREIGN KEY REFERENCES ShipHeader(ShippingID),
OrderRentalDetailID int,
Qty int
)
CREATE TABLE OrderSalesDetail
(
OrderSalesDetailID int identity primary key,
OrderID int FOREIGN KEY REFERENCES OrderHeader(OrderID),
ItemName varchar(30),
Qty int,
SiteID int,
)
CREATE TABLE ShipHeader
(
ShippingID int identity primary key,
Type int,
SiteID int,
ActionDate datetime
)--Use Type 1 = "Ship" Type 2 = "Return"
CREATE TABLE ShipDetail
(
ShipDetailID int identity primary key,
ShippingID int NOT NULL FOREIGN KEY REFERENCES ShipHeader(ShippingID),
OrderSalesDetailID int,
Qty int
)