How to add a modifier to a collection? My goal is to reduce the faces of an object using the decimate modifier.
The object I'm editing has lots of vertex groups.
Blender 2.8 only lets me add the decimate modifier to a single group at once which would take quite some time. I have already put all groups in a single collection.

How can I add the decimate modifier to the entire collection?

Do I have to add the modifier group by group?
You have to join the objects together and then apply the modifier and then you can separate by loose parts.
Or

Add the modifier to one object.
Select all the other objects and then the one with modifier last.
Then Ctrl+L to copy modifiers to all selected objects.