Can Context DFF field be made read only?

On work orders we have context based flexfields, so based on what value is put in the context field, certain flexfields are shown.

Through a customization, the context value is brought over from the Asset screen upon saving of the work order.

I know that you can use the personalization ($RO$) to make dff segments read only. My questions is, is it possible to make the context field read only?

Thanks

Daryl