It’s not easy for sure and I’m not a designer or ui/ux expert - just been around maps for a while
I agree with you that the point itself could show that it’s special - or - rely on users tapping/clicking it and then show all the info
In a sense, maybe conveying that the point has more than one data point attached to it isn’t critical - as long as you can see everything inside when clicking it!
Feel free to email me, would love to jam/chat about this!