VetRX is basically vicks vaporub, it won't treat anything. It may help with symptoms, but it won't cure anything. If there is an underlying virus or bacteria, that has to be dealt with.
Respiratory virus's are not uncommon, and some can be brought in by wild birds. If you continue to see issues, and more birds are having symptoms, I would guess it may be that.
If there are resources there for testing, you could have labs done on one with the runny nose, to ID if it's viral...
Where are you, generally, in the world?
Sometimes they can have a bit of food or debris that partially blocks the airway and it can cause what is called stridor, which is a wheezy or honking sound. If it's that then it usually resolves on it's own. Sometimes it doesn't last long, sometimes...