Building a composite attribute from sets of attributes

[Rod Widdowson]

Without understanding what your desired endpoint is (and indeed the way that things are deployed in the field to any level of detail) all I can give is pure developers point of view.

If the idea is that you need an IdPAttribute whose values are IdPAtributes why not start with a class that implements IdPAttributeValue which does this?

You'd then need to write a Resolver and some Encoders and of course the parsers for these, plus of course any special filtering you need, but it's all public interfaces.

I'd suggest you look at where XMLObjectAttributeValue occurs in the source since that gives you a good idea of the plug points that would need

To re-emphasise, I have no idea whether this is the best domain specific way to approach this.