Question 1: Can I use くれる if somebody gave something to my team/company/class? くれる is mainly used for "to me" and "to us". So the answer is YES, because "my team/company/class" and "humanity" include "me". If aliens gave something to humanity = もしエイリアンが人類に何かをくれるなら Can I use くれる if somebody outside of my team gave something to a member of my team or somebody outside of my class(work) gave something to my classmate(co-worker)? YES, for example: He gave some books to my co-worker. = 彼は私の同僚に何冊かの本をくれた。 (かれは わたしの どうりょうに なんさつかの ほんを くれた。) *You can also use あげる in this case. Question 2: あげる and くれる which one to use if somebody of my in-group gave something to another person of my in-group? The answer is あげる. My father gave something to my mother. (父は母に何かをあげた。) My mother gave something to my brother. (母は兄/弟に何かをあげた。) My younger brother gave something to my older sister. (弟は姉に何かをあげた。) One of my close friends gave something to another my close friend. (私の親友はもう一人の親友に何かをあげた。) One classmate gave something to another my classmate. (あるクラスメートがもう一人のクラスメートに何かをあげた。) *In these cases, all are "the third person(s)" for the speaker, so we use あげる. NOTE: Depending on the person, dialect, etc, there are cases that they use くれる. I hope this helps you.

あげる is giving something from the speaker's point of view. くれる is someone else giving something to the speaker from the speaker's point of view. When it's in third person, e.g. someone that is not the speaker gives something to someone that is not the speaker, you look at it from the receiver's point of view. エイリアンが何かを人類にくれた Aliens gave something to humanity (This is from the receiver's point of view, someone gave them something) So in both questions, you should use くれる. Someone gave something to you? くれる. Someone gave something to someone in your family? Look at it from the receiver's eyes and use くれる. The same goes for some stranger giving something to another stranger etc.

maybe this will help you: https://en.wikibooks.org/wiki/Japanese/Lessons/Giving_and_Receiving