Config
You can create a new rank and then simply give players the permission permissionbalance.multiple.<new rank>. The plugin will handle the rest! It automatically checks which maximum balance permission the player has, and will apply it to all transactions.

Unfortunately, there is a limitation that the plugin essentially acts as a maximum cap. This means, the player can still be paid by other players (and they will lose their money) but the player will only receive enough money to hit the cap. Similar concepts apply to other transactions: the player can sell items, and will lose them, regardless of if the max balance has been reached or not. See example case below:
Scenario:

• Player 1 has cap of 5k
• Player 2 has cap of 10k
• Player 1 has balance of 0
• Player 2 has balance of 10k

• Player 2 pays Player 1 7.5k

• Player 1 has balance of 5k
• Player 2 has balance of 2.5k

Commands
Reload config | /permissionbalance reload | permissionbalance.admin.reload