I would suggest one of the ways (or maybe you can find a proper combination of both):
- Way 1 "Do them like trade filter do". When you zoom out so that multiple resource probes got groupped, show maximum for each resource a probe reports in said group, then on hovering over the value show the probe of this group that reports this value
- Way 2 "Do them by sector with heatmap". Allow grouping of probes only within one sector, allow player to chose one resource they are after and make a heatmap of sectors where said resource is reported by at least one probe
way2 is bit more neat in case multiple nearby sectors report about the same level of a resource - in that case way1 will show only one possible way to go, where way2 will indicate there are multiple options to be chosen from
Also way2 may then be implemented over trade filter to show offers 1 cr cheper but in two sectors away rather then more profitable but on other end of the galaxy (guess, thats somewhat managable now by ajusting zoom level)