We need to create an ntp server that syncs against other ntp servers but gives its client a modified utc.
For example, it will receive utc 5:17 pm but it's clients will receive utc 7:17pm.
I'll describe the current situation so you'll understand the reason for this need. Some of the terms I'll use are from the world of mainframe so I'll try to explain them.
We have a number of LPARS (similar to VM guest) on a single physical machine. The LPARS are grouped in a number of Sysplexes (similar to cluster). The LPARS in each Sysplex are synced using an ETS that is connected to the machine and modifies the clock of each LPAR directly.
Years ago someone thought it will be a great idea to set the ETS's clock to the local time (The site is not in UTC±00:00). The LPARs get the UTC from the ETS clock. We can't change the ETS clock to the real UTC without effecting all of the machine. We want to test the change in test environments first. We can change the sync method to STP (sysplex time protocol) that manages each Sysplex separately. This method uses external ntp server.
So first we want to change one sysplex to use STP that gets a false UTC and perform testing if we set the STP correctly. And then change the utc and perform testing that the system can work with real utc.