Hi Kellia,
Welcome to the blog.
Not too big of a problem other than cooking that much size at one. T-bone/porterhouse steaks are mostly strip steaks. That big side is just a strip steak. The difference between the t-bone and the porterhouse is just the size of the meat on the other side of the bone which is tenderloin (filet)—bigger in the porterhouse.
I tend not to do this pan-searing method with bone-containing cuts since the meat will shrink some and the bone will prevent the area near it from searing. Not a big issue but that is why I usually grill my porterhouse steaks.
So assuming you don't care if a bit of the porterhouse does not sear much (the rest will sear and it all will cook fine), what are the issues you will face? The bone will delay the cooking slightly (not a lot) and the porterhouses probably are bigger overall. Lastly, the filet part of the porterhouse will overcook-it just tends to cook faster but that always happens and it can tolerate it and still be great.
So I would preheat the oven with a large sheet pan, sear the porterhouse first and transfer to the oven, then immediately sear the strip steaks (I assume you don't he a stovetop skillet large enough to do all four at once). Transfer the strips steaks and check the temp on the porterhouses (probably not done yet).
The porterhouse will probably be done first thanks to the headstart, move to a plate and tent with foil while the strips finish.
No rack or foil but you MUST use an instant-read thermometer to pull this off or you will be flying blind and most likely will crash. If you don't he one, they are about $10 at a big box store (Home Depot/Lowes, Walmart may or may not he one).
Good luck.
Dan