Modify Drupal Ubercart

We need a change to Drupal Ubercart. The situation is this: Our customers are hotels. In their account information, it says the number of rooms this hotel has. When they order a product (products are TV channels), they order per month. So a hotel will for example order a TV channel for 2 months. But the price in Ubercart is per product, per month. What we need is that Drupal Ubercart automatically multiplies the price by the number of rooms the customer has. Please see the attached pictures to fully understand.