Dear hankuri: I regret that I do not know of a book likely to be just what you want. At the moment I cannot think of a way to use a preposition with "regret" . I think that as a transitive verb, a noun or clause as its object should give you the meaning you desire. I'm 83, and have forgotten all the grammar I ever knew.
As to the two simultaneous events in US, they might occur in the same time zone. They might happen on the East Coast, or in the Mid-West.
Keep posting until some of our experts notice, and give you better answers than I can. We have some very bright and helpful people who just have not happened to see your posts yet. Don't get discouraged. Try some other examples. My very best wishes to you, Bill Hunt