Overrun as part of a charge

[Scottlang]

Now, the answer is probably in the title of this, but:
If you charge to attack opponent A, but opponent B is in the way, can you use the overrun ability to get past/overrun opponent B to attack opponent A??
Because I know my players are going to question the heck out of this.

[Zombimode]

Not in a way you like.

Overrun (and trample) have action costs on their own. Thus you can overrun (or trample) but then you will likely not have enough actions to make a normal attack.

[Crake]

An opponent has the option to avoid an overrun. If they do so, the overrun doesn't happen and you can continue onward toward your target. So if you can make the overrun sound threatening enough that the player will take the option to move out of the way, you can just continue charging over to the other person.

I would probably pair it with a bluff/sense motive to see that they aren't the attacker's real focus if they do choose to get out of the way, just so they have a chance to redeem themselves instead of moving out or position to leave their friends vulnerable.

[ViperMagnum357]

The only way I know of without a mount or the Trample (EX) attack is 3rd party: the Demolisher, a Dwarf only PRC from Mongoose's Quintessential Dwarf 2 has a bunch of charge related abilities. Among them is the ability to charge through enemy occupied squares, giving you a free overrun, and a separate ability that allows you to knock an overrun opponent 10 feet per point of Strength modifier in addition to flooring them. The big winner is with a dungeoncrasher fighter: when you bullrush someone as a charge and follow, as long as you win by at least 1 point you push them back your entire movement distance, then knock them flying another 10 feet per point of Strength modifier.

[Eladrinblade]

If the overrun happens, it uses up your standard action.