Is it possible to use more than two jammers in the same building?

I think if you ask such questions, you will know the basic knowledge of gps blocker, so I won't tell you what you already know. If you want to use more than two signal shields in the same building, you need to consider many things.
First, you need to determine whether the jamming radius of the jammer should cross. If so, they must work with different frequency bands to avoid mutual interference. If the interference radii between jammers do not intersect, two jammers of the same type can be used. Moreover, if you block signal jammers with two different frequencies, you can forget to worry about their interference in work. Therefore, make a wise choice and remember that there are some jammers.