How to remove isolated elements in a finite elements application?

Hello!

I'm working on a Finite Elements program, and I kee on having the same problem: sometimes, during some iterations of my programs, a group of elements gets isolated from the main strutucture, having, thus, no kind of restriciton of movement. This results in numerical errors, and, in the best scenario, more time to run the code. My first atempt in dealing with this issue was to let the error happen, and then remove the elements with NaN coordinates. I imagine this is not recommended, but it was the only thing at the time. Now I'm trying to come up with a better solution, but I can't think of any other ways to implement such an element remover.

One idea that has occured to me is that, since these elements do not have any connection to any other in the structure, they will form an uncoupled system in the stiffness matrix, an maybe this be exploit to remove them before the calculations. But I can't think of a way to implement this. Besides, since I intend to use my program with structures containing millions of elements, I don't know if this is an efficient method.

Whats do you guys suggest to solve my issue? I attached an image of the isolated group of elements.