As a collective, jointly, together, in unison, simultaneously, cohesively, en masse, as a whole, in concert, as one unit, collaboratively, in tandem, as a team, working in unison, in a concerted effort, congregated, as a mob, in a swarm, banded together, in a horde, organized as a unit, combined efforts, all together, as a gathering, in a pack, pooled together, unitedly, in a company. These are all synonyms that can be used in place of the phrase "as a group" depending on the context and tone of the sentence.