"Mam grupę dobrych przyjaciół."

Translation: I have a group of good friends.

[rvabbott]

Is "dobrych przyjaciół" genitive or accusitive plural? Does the "of" indicate possession, making it genitive?
.

[immery]

it is both in general, but genitive here.

[deactivated user]

why is "i have a good group of friends" marked as incorrect?

[mihxal]

Because the friends are good not the group.

[domnelson]

That would be "mam dobrą grupę przyjaciół".

[XennialStar2001]

I don't I wish I have one

[Euhan1]

"I wish I had one."

[mihxal]

But he doesn't wish.

[Euhan1]

Then I wish she (or he, as far as I can tell) did. ;)

[Ash473779]

Why is 'good friends' in the genitive case here? I thought that the genitive case was used for negative sentences, after certain prepositions and to indicate possession. In this example, what exactly do the 'good friends' possess that puts them into the genitive case?

[Jellei]

If anything, then something would have to possess them (okay, sounds like a need for exorcisms) for it to be Genitive.

The answer is "of". If you have 'of', it will (almost?) always be Genitive.

[monteirorogerio]

Would "Mam dobrą grupy przyjaciół." be "I have a good group of friends."?

[Jellei]

Almost. "dobrą grupy" don't match each other grammatically, "mam" needs Genitive, which will be "dobrą grupę". Just like it's "grupę" in the main answer here.

[Frizzank2]

It is called a partitive genitive. It is used for phrases that require "of" to complete the meaning of a word consisting of "parts." e.g. part of, piece of, half of, group of, mass of, bag of, handful of, etc.

[AlexPhysique]

I have a group of the good friends - is wrong.

[alik1989]

Yes, it is.