This can be easily done by adding additional Pricing Levels under Settings > Pricing Levels & Billing Rates. Each additional Pricing Level created, adds another price column to both your Billing/Labour Rates and Price List items.
For example, in the image below note how there is an additional price column on each of the Billing Rates that corresponds to each Pricing Level:
The Pricing Levels can be set on each Customer record as the default Pricing Level to be used when creating Jobs for that Customer:
So when a Job is created for the Customer, "Rendezvous Grand", the "Commercial" Pricing Level will apply to all labour and materials entered on the Job:
Tradify then indexes the corresponding charge out rate to use when billing for labour based on the selected Pricing Level.
In the example provided above the Commercial charge out rate set for the "Standard" Billing/Labour Rate is $85.00 per hour. Labour will therefore be charged out at $85.00 per hour on this Job when the "Standard" Billing/Labour Rate is used:
More information on setting up Pricing Levels and Billing Rate can be found here.