I have about 5 teams trying to push for their stuff to be done first right now

I give them a reasonable explanation that their stuff is less important to some others and they seem to understand on the meeting but the next day they are back to pushing I work on their stuff immediately

Part of the problem is how the resources are allocated, these teams grow while ours stays the same size as they are deemed more important and they all want to look as good as they can on the back of our work