The only workaround I can think of is creating non persistent objects where you create that extra attribute and copy the whole lot over. Then show the NP objects to the end user in the right sort. But if you need to interact with those objects it creates an extra layer of complexity because you then have to find the corresponding object again from the non persistent version.
Regards,
Ronald
I think calculating and storing the value as an attribute makes sense, and that is how I would have approached it.
Is there any reason you don’t want to do this?