Bulk Update Desk Picklist via API call

We are using Zoho Desk for our ticketing and system and bill our time against external jobs that other departments in our company are working on. In the Zoho ticket the technicians currently enter the job or department information manually. While this is working, it does cause an issues where the technicians are not aware that we can no longer bill against a specific job and the costs should go to the appropriate overhead group running the job. We are looking to add a populated picklist to the to replace the existing data entry filed that gets updated every couple of days with values being removed or added as needed. We have created a test ticket form with a picklist that denotes billable active jobs in that we want to be able update every couple of days. The list will be exported from our Accounting system will get updated throughout the daily and currently consists of over 4000 values and is growing. We currently are doing a manual bulk remove and replace of the data as we test out the other functions in the new form

I am envisioning that we would be able to bulk remove the existing picklist values and replace them with the new set of values on a schedule via API calls. Can we do bulk replacements like this with the API or are we limited to only adding new single values and removing single values? Can you point us at a starting point?

Thanks