How to allocate MS PROJECT labor resources for 1 task?

Question

Project management

Greetings.
Given: Contractor 1(01/01/1000-01/01/1001), Contractor 2(06/01/1000-06/01/1001), Contractor 3(01/01/1001-01/01/1002).
Available sequentially at intervals of half a year during the year.
The task is 2 years long.
If the current date is 01.01.1000, when adding resources, only the first one has 100% availability, the rest have 0 and they are not involved in any way for the entire time period.
How to ensure that they complete the task full time as a new performer is hired every six months?
First six months performer 1, second six months performer 1 + 2, second year performer 2+3, second six months 2 years third performer.