Text field - autonomous text

I am working with a title block.
I would like to insert a text field object that remains unique across block instances.

What I mean is that the block ordinarily would be an exact clone for every block instance.
In this case i want some text not to be cloned but rather remain with a unique text that ‘lives inside’ the block. This could be i.e. a revision description for each layout sheet.

Is this possible?

If not, I would like to request it as a future feature.