Use a cross reference as an Attribute in Product Context

Hi pricing experts,

I use the cross references in the inventory (mtl_cross_references) to link our item with item number of our competitors.

Here a short example:

For item are 5 cross references of the reference type 'competitior number' defined.

My inventory item id:123456

Competitor numbers: 123 C1

                                         456 C2

                                         789 C3

Now I want to use this cross references as an attribute of the conext product, because I want to maintain the selling prices of my competitors in price list.

By doing so it's possible to calculate the same order to the conditions of a competitor. That would by very nice...

I've already configured my new pricing context for this issue, but I can't handle the User value string in the Attribute Mapping.