I can suggest that you try the following steps:
1) Bind the Grid and Map controls to the same GeoJSON data source.
2) Add information to the GeoJSON data about the location of the tooltips.
3) Attach to the shapeCreated event of Map and where you can create the marker with the desired location and text from the data source. Here you can also add a custom id to the element.
4) Attach to the change event of the grid where you can find the map's marker by the custom shape id and display the tooltip
5) Use CSS in order to hide the markers.
I have created such an integration for the first two countries from the GeoJSON data source in the attachment. Please give it a try and then tell me how it goes.
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