IMO, you should be able to issue specific commands to planets in sectors, though probably at the cost of some influence per order.
I had a planet in a sector where I had previously built a building that required special resources, but was no longer able to supply this resource. Consequently, the game would spam me with warnings that a sector was missing resources (confusingly showing 2 power and 1 of the special resource), but I was unable to do anything about it due to the planet being in a sector. I ended up removing the planet from the sector (at 25 influence cost), demolished the building, and then re-added it to the sector, to get rid of the spam. Not quite optimal.
Also, those warnings should tell you on which planet there is a problem and / or I really want to be able to search for specific types of buildings, at the very least those using strategic resources. Finding that one planet that was generating the spam messages was a pain in the asteroid, since I had to manually go through every planet in the sector and screen the surface by eye. Not fun.