This depends on a LOT of factors...
- Class
- Build
- Gear Level
- Solo or Multi-bot
Generally speaking DB gives us a lot of advantages over the non-bot player. Grouping mobs and building density is definitely not one of them.
You can adjust your mob counts and radius to whatever works best for you, but this requires testing (Take a look in Guides section of forum to see example Trinity settings, but be warned... You have to find what's right for you).
What you will find in this process is that the bot
doesn't run between groups of mobs, back and forth, until the mobs combine. If they meet your density requirement, it will stop and fight. If they do not meet your density settings, it ignores them and keeps going.
In short, modifying your Trinity settings will have the desired effect SOMETIMES. However, it doesn't have a function for grouping enemies. It is a Binary of "yes/no" to attack when it sees an enemy. It often leads to less than optimal density, but you're using a bot... Sub-Optimal is okay because it can run 24/7.