I'll try to expand on Michael's terse answer.
Basically, no. Objectivity is usually taken to mean something like "mind-independent". Exactly what this means is up for some wiggle-room (what is objective? or what kinds of things can be objective?), but in most cases it's fairly clear cut.
Subjectivity, conversely, is "mind-depended". Again, it's pretty clear, but it's up for debate precisely what this means (is the existence of emotions subjective? Some would say trivially so, because there has to be a mind to have an emotion, but subjectivity is usually taken to be an epistemic notion, so it's not so clear if this is a good use of the term).
Even if something is dependent on 6 billion minds, it's still mind-dependent.
What are the intuitions behind your question? I can't say for sure, but I can speculate:
(1) Objectivity/subjectivity has a functional flavor to them. It's almost like an objective truth is one that you can 'bump into', that resists you or imposes itself on you. Mass agreement might have this kind of cognitive 'substance'.
(2) A subjective truth is one where there can be genuine disagreement, because the facts of the case depend on an individual's standpoint, and disputes can't be resolved with reference to external facts. If everyone agrees on something, then there can't be disagreement.
(3) It might have the same impulse as "If everyone decided that cats were dogs, then they would be." If we take this to be a definition, then yeah, if everyone decided cat meant dog, then cat means dog. It doesn't mean that cats are the same as dogs, it's just that we've decided to use the words in that way.
This question could have other possible motivations, but I think these cover the most likely ones. Feel free to explain more or ask questions.