Choose predefined xs:attributeGroup - Help needed

Hi all,

I'm actually trying to design an XML-Schema that should be universally
used within form creation (Xforms, XSL-t processing, and XML validation
check). I'm actually designing one that should be representing a graph
of all possible valid attribute combination within an element. Below a
simple example:

Here a basic Product element in XML:

<Product pr_name="ONE" pr_Info="A"/>

Now, according to some business rules, let's say that all products named
"ONE" should have their pr_Info attribute set to either A or B, and all
products named "TWO" should have their pr_Info attribute set to either C
or D.

A possible solution is to design an XML-schema proposing a choice of all
Product element representing all possible combination according to their
pr_Name.

I'm looking to have to design it with the use of attribute groups, such
as (pseudo-code below):

attributeGroupA is:
	Attribute name="pr_Info" value=restriction on either A or B
attributeGroupB is:
	Attribute name="pr_Info" value=restriction on either C or D

Element product
	start choice
		choice 1: attribute pr_Name = ONE and attributeGroupA
		choice 2: attribute pr_Name = TWO and attributeGroupB
	end choice
/Element

Which will correspond to validate XML data such as:

<Product pr_name="ONE" pr_Info="A"/>
<Product pr_name="TWO" pr_Info="C"/>
<Product pr_name="ONE" pr_Info="B"/>
(...)

Any idea would be greatful

Best regards ;-)

Lawrence Michel