Assume that you already have or can manually create some unique id for each pushpin/table cell pair. Then after you create each pushpin, you can assign this info to its metadata:
var pushpin = new Microsoft.Maps.Pushpin(map.getCenter(), null);
pushpin.metadata = { id: "Some Id" };
// ......
// Other work like binding infobox and mouseover event
Now Let's say you eventually add the pushpins to map like this:
var pushpins = [....];
var layer = new Microsoft.Maps.Layer();
layer.add(pushpins);
map.layers.insert(layer);
And on the table side, bind the same id to a custom data attribute of the table cell:
<td data-pushpinId="Some Id">Cell A</td>
When you hover on the table cell, get its data-pushpinId
and find the corresponding pushpin on the layer, then invoke its mouse over event.
var pushpinId = tableCell.getAttribute("data-pushpinId");
var pushpin = layer.getPrimitives().find((pushpin) => pushpin.metadata.id === pushpinId);
pushpin && pushpin.mouseover.invoke();