How do I correct this, but say the same thing.

"The idea is that the most powerful group uses their wealth to take advantage of groups with less influence."'

The idea is that the group with the most wealth takes advantage of those with less influence.

The wealthiest, therefore, the most influential group, takes advantage of those groups with less influence, as a concept.

The idea is that, in groups, the wealthiest will always be the most influential, and, always, take advantage of those with less wealth, therefore less influence.