I'm wondering if one can use the word "aggregation" to mean a team or a collaboration of sorts, or even a certain collection of individuals in general, not just objects. Any thoughts?
Aggregation can certainly be used to mean a collection of individuals.
I will note that, in my mind at least, aggregation tends to imply a level of disorganization or heterogeneity that I think somewhat conflicts with the idea of a formalized team. So, while it works well for an ad hoc collaboration working towards a particular end, I probably wouldn't use it for a group that is otherwise already entangled.
In a word, no.
While aggregation can technically be used to describe a group of individuals, in common modern usage it only describes a group of objects.
Simon Jester's second example shows a usage of the word that has generally gone out of style.
Language is an ever-evolving animal, and majority usage rules – even if the dictionary tells you otherwise. Dictionaries are outdated almost the moment they are published, especially in this day and age. (Opinion)
If you must use aggregation to describe a group of individuals, try focusing on a quality (i.e. object) that the group shares, e.g.
In a word, yes.
Here's one of the definitions according to the OED:
And from the quotations: