Disable caching if pricing changes on customer group?

I am currently doing a highly custom integration of opencart. I had to make the pricing change on customer group and the quantity bought. Will the caching cause users to see the wrong prices?

Does anyone have suggestions on how to do this effectively? I made a model for pricing. The system cart.php override was not as clean as I would of hoped. I had to add a function called setModel() on cart which runs in the main index.php file. This gives cart.php access to the main model object. Then cart.php can access the pricing model file. I'm hoping since objects are passed by reference this shouldn't cause any memory issues.

I'm finding that although opencart is MVC it does not have the best object oriented design. There is no real instantiation, setters, or getters. Everything is basically accessed statically.

I did start using vqmod but stopped just because it was easier to develop right in the code. I will probably do a file compare in the end and put all the changes in vqmod.

If anyone has ideas or suggestions it would be greatly appreciated.