Either is OK. With collective nouns, you can typically use either a singular form to refer to the group, or a plural form to refer to the members of the group. Sometimes you use plural to deliberately emphasise that you are taking about the individuals. Sometimes, (as I suspect is the case here) people use the plural because it seems more natural because of the implicit plural of 'us'.

the plural actually comes from "us" rather than "group" - it's the same as if you said "a group of people are going to hold a party" or "we are going to hold a party"