It looks to me like catfacing. See images on this google search for "catfacing" -- they look a lot like yours.
According to this web page there is no cure; the problem is related to planting out and can only be prevented. They mention that large-fruit varieties are most susceptible, so your Brandy Boy and Porterhouse may be at risk if they were planted the same way. Your grapes might be safer. They also say:
...disturbances in flower production such as low temperature, injury 3-weeks before flowers are mature, especially in early plantings, but also with injury from growth regulators such as 2,4-d. Pruning and high nitrogen can also aggravate the problem.
Some useful references are included at the bottom of that page; the [second reference to a World Vegetable Center article on catfacing gives explicit control instructions to help prevent it next season.
This Colorado State Extension tomato problems fact sheet shows pictures of catfacing next to blossom end rot. If you compare the two photos there, yours looks much more like catfacing than BER.
Catfacing (Figure 10) is a term that describes tomato fruit that is misshapen, with scars and holes in the blossom end. The cause is thought to be cold weather during blossoming and perhaps high levels of nitrogen. To manage it, avoid setting out transplants too early in the season.
They don't come out and say it, but again there's no cure, only prevention.