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Have you inspected the bark on each tree very closely, from the ground up, looking for evidence of borers?

...also:

1) how old are these trees?

2) were they bare-root, container, or B&B?

3) do you install them, or have it done?

Marco, your Bradford problem looks different than what I am suddenly seeing around here. Did this start with the outer eight inches or so of branches turning brown? That just looks different than the fireblight which seems to have modified itself to attack the Bradford clone monocultures Lowes and Homedespot have created.

toronado,
It could still easily be fireblight (not saying that is what it is), as FB also makes cankers. Entry through a flower on a small branch along a larger branch, then working its way downward over the course of the growing season. That's one way to produce a canker, resulting in what we see in the pictures, but not the only way.

Marco, as much as most of us here don't like these pears, I'm still sorry to have to tell you that you are probable better off removing your remaining pears, and planting something different from another family of plants. If you are open to this, ask here, and many people will be happy to help you if you will provide relevant information.

JMHO
Arktrees