Gary,
You have several options, but the most appropriate one is to insulate the line. You could also seal any possible entry points beneath the dripping suction line or fashion a drip tray with a drain to collect the condensate, but insulating the line seems the best solution.
If you shut down the AC unit and let the line dry out, you might use foam sprays with care and proper masking, insulating tape wraps, or foam rubber pipe insulators secured with nylon wire ties. There could be other solutions as well.
Since this issue is happening with one AC unit, it’s likely that the others might experience the same problem. Therefore, you should address the issue with the current unit and apply the same solution to the others.