Multiple flags, one flagpole

I added my first flagpole the other day and want to start adding more. But I’m not sure how to handle when there is more than one flag on the same pole. Example: around here it is pretty common to both see a USA flag and a Canadian flag (the red maple leaf) on the same pole.

For a single flag:

country=US
flag:name=United States
flag:type=national
flag:wikidata=Q42537
man_made=flagpole
subject=United States
subject:wikidata=Q30

But if there is also a Canadian flag on the same pole, then

flag:name=Canada would introduce identical keys on the same object. Same can be said for several other duplicate keys.

Perhaps add another node to the same spot with the Canadian flag. If necessary you can use the layer tag to specify which is above/below the other.

How about flag:name=United States; Canada?

Sorry if it’s a basic question. I am still trying to get a feel for OSM syntax.

You are correct!

If the flagpole routinely flies multiple flags at the same time, combine their values top to bottom using the semicolon value separator. For example, many post offices and other public buildings in the United States flag the U.S. flag above the POW/MIA flag: tag the single man_made=flagpole as flag:wikidata=Q42537;Q1463762.

Don’t be, because it’s a good question!

Tag:man_made=flagpole - OpenStreetMap Wiki says that ; is correct, in top downwards order but also tag the wikidata the same way e.g. flag:wikidata=Q42537;Q1463762

I’ve also seen a cross-bar flagpole (e.g. Crossarm Yardarm Flagpoles | Fly Two Flags with Style) at a shooting range with AU flag on the main pole, club flag on the left and red range-safety / shooting in progress on the right! Not sure how that one gets tagged?