It’s been a while since I wrote about subject-verb agreement. In fact, it’s been close to a year. I’ll leave the searching to you, though. I don’t want to take away all the fun.
The concept of agreement means that we want the same “number” (singular or plural) for our subject and our verb. When they don’t agree, we notice. Not because we know some arcane rule. Because it just sounds wrong. Very, painfully, obviously wrong. Most of the time, anyway.
The cat were lazing in the window.
How many cats? Only one? Then it’s “was lazing,” not “were.” Two or more? Then we need to fix “cats” and leave “were” alone. That one’s pretty clear, and a simple contextual reading will probably suffice for clarification. (This bypasses the rules for the subjunctive mood in English, which does weird things with number and tense, like “God save the queen” and “if I were you.” This isn’t that, and I’m not going there right now.)
But look at this one:
The A-group, as he called his team, were clocking out at the end of the shift.
On a quick read that sounds all right, maybe. Depends on how you like your collective nouns. They swing, you know. Singular or plural, either way, depending on the concept of “notional concord.” It also matters whether you’re an AmE or BrE speaker/writer. In the United States, we tend to treat “team” as a singular entity, like we do with companies. “Apple is announcing a new gadget.” “The team is entering the stadium.” (BrE speakers/writers tend to say “Apple are announcing a new gadget.” Looks weird to me, but it’s their style.) That matters, because the audience brings its expectations along to your work. What are your readers likely to expect? Go with what they’ll think. It’ll save you hassle in the long run (fewer 1-star reviews from grammar pedants worse than me).
If you’re an AmE speaker/writer, I suggest going with “The A-group, as he called his team, was clocking out. . . .” No one will argue with you, I don’t think. To check the flow and sense of it, remove what’s set off by the commas. “The A-group was clocking out.” If that sounds right to you in that form, it’s still right when you put that phrase back in: “The A-group, as he called his team, was clocking out.”
Certainly one could argue that a team comprises several members, and therefore could be considered as plural. That’s notional concord at work. What sounds right to you? What makes sense to you? After you figure that out, then ask the same about your audience. What will make them scream? Pick the other one.