Is the pronoun 大家 (everybody) a subject only? In a Cantonese forums, someone posted a question:  &quot; how to say 'each other?' or 'one another' in Chinese&quot;
One of the suggestion was:

I  thought the simplest way is just to say 大家？
They don't like each other - 佢哋唔中意大家

And my reply to this answer was:

No, 大家 means &quot;everybody &quot;
In &quot;大家都唔鍾意佢哋&quot; ( everybody dislike them)
大家 is the subject, and 佢哋 is the object
If the subject and object switch places in the above sentence, you have to replace 大家 with &quot; 所有人&quot; or &quot; 全部人&quot; and place the object before the subject.
&quot;所有人佢哋都唔鍾意&quot; / &quot;全部人佢哋都唔鍾意&quot;
*you cannot write 大家佢哋都唔鍾意
*佢哋唔鍾意所有人 or 佢哋唔鍾意全部人 sound awkward.
More examples:
大家一齊停手 ( everybody stop at once)
大家都有好處 ( everybody would benefit)

I don't think I have done a good job explaining why 大家 (everybody) cannot be the object for the subject 佢哋. It is a pronoun, and pronouns should be able to become subjects or objects. Would that be because 佢哋 is also a pronoun?
I also know 佢哋唔鍾意所有人 or 佢哋唔鍾意全部人 sound awkward, but can't explain why.
While 大家 means 'everyone', it refers to 'everyone' in a group of people that is implied in the sentence, or everyone in close proximity

佢哋唔鍾意大家


大家 in this case implies everyone within the group of '佢哋', which is essentially 'each other'. Also this sentence sounds perfectly natural, I hear this a lot when people are referring to couples who don't actually like each other

大家好


大家 here refers to everyone that you are speaking to, basically 'hey everyone'

大家都唔鍾意佢哋


There is an implicit subgroup '大家' where everyone in that group or everyone here dislikes 佢哋, 'everyone (here) dislikes them'

大家咁話啦


'You too', 'same'

大家 can definitely be used for 'each other', however it is not the only usage, and there is not a direct one to one translation for 大家 in english.

In other special cases, for 'each other' / 'one another' you could use:

'彼此'相愛


to love each other

'互相'鼓勵


to encourage each other

'自相'殘殺


to hurt and fight each other