Even though they're vaccinated it still sounds like kennel cough. If you do a search for honking cough that is what's gonna come up. It's also highly contagious which explains why they all have it. A reverse sneeze sounds similar but it would be unlikely for all the dogs to have that.
You need to boost their immune system. Give them vits A, B, D & E. Also coconut oil and honey are good for this also. This link has some great things you can try including a cough syrup.