Entities and pivots

Okay I’m running into this again in a library I’m making - seriously, how do people usually handle pivots in a model? In this case I have a users table and model, a groups table and model, and a groups_users pivot table for the many-to-many... If I want to get a user’s groups what does that look like in the model or entity? Anyone have ideas on best practices, common solutions? Currently I’m doing a join but only selecting the target table, but I feel like that has neither the efficient g of just grabbing IDs nor the robustness of returning an actual entity.