You can copy a Custom Fact (and its citation(s) and associated image) and paste to other persons in their nuclear family:
Make one Custom Fact for whatever
Right Click - Copy
Navigate to a person where you want to paste. Select any fact for that person.
Right Click > Paste
You will get a pop-up page where you can check those relatives listed below to be pasted in one operation::
So, you can copy and paste to a batch in pretty quick order (say for residence).
But, if the tag is for a scattered group of people that don't belong to a family (ie Civil War Union Survived, or Civil War Confederate Casualty), you almost have to do it one person at a time.