Adding Same Map Location to separate collection in Lightroom

Wonder if anybody can help please. New to Lightroom and finding my way but this has me stumpped. My SLR doesnt have GPS so I am manually adding photos to the Map to give a rough idea of where photos were taken.  I have 2 collections (Holday photos from 2 separate years but at the same destination). I add photos from 1 collection to the map but how can I get that location pin to show when I click into the other collection? As far as I can see I have to drag a new location on. I would rather have all the photos in one location folder? Can anybody help?

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