Okay, now I get the jest of your post.
I thought you meant multiple attacks on a particular day, i.e. several subway stations and buses attacked.
whoops, not jest, gist.
No, its common for them to have multiple attacks on one city, they've done that everywhere, Spain, Iraq, 9/11. They as yet haven't tried to attack two countries in one day, not on the scale of the London attack at least. To do so would probably require enough communication between continents to raise suspicion, and thwart the attack.