It is a collective noun, so it depends on what rule you might follow. Here, in the United States, we treat almost every collective noun as singular despite its being plural in nature. For example:
"The group has done a good job presenting its project."
"The jury is deliberating the man's fate."
"England is going to win its match tonight."
"The government has passed another one of its stupid laws."
"The Johnson family is having dinner at its own house for once."
However, the British and other English-speaking countries often treat the collective nouns above as either singular or plural depending upon the context. When they want to talk about the "group as a whole", they use a singular verb; when they want to talk about the "individual members of the group", they use a plural verb. For example:
"The group (members) have done a good job presenting their project."
"The jury (members) are deliberating the man's fate."
"England are going to win their match tonight." (i.e. "The England
"The government (members) have passed another one of their stupid laws."
"The Johnson family (members) are having dinner at their own house for
There are nouns that are always treated as plural, no matter what English-speaking country you might be in. Some of those are collective nouns involving a people of a country:
The French are...
The English are...
The Spanish are...
Also everyone uses a plural with the collective noun "police":
"The police are (not is) just doing their job."
However, this could differ when talking about specific police agencies by name:
"The FBI (are / is) investigating the situation to determine what
charges (they / it) may file."
"The IRS (know / knows) everything about my finances."
I hope that might have helped you understand this difficult grammatical concept. Take care and good luck in your studies!
P.S. I had not seen the word "every" used above as in "every group has done" prior to my writing this answer. When the word "every" precedes a collective noun, it will always be singular.