The situation is the following: I have been researching, in an experimental science, the capabilities of a new way how to perform a given experiment. Due to the challenging nature of the project, I have encountered several pitfalls until now and after several years have found a main line of projects within this scope that can yield a good outcome. The peril: a new postdoc will join our group and he already stated his main interest in also working in the same experiment.
Since I feel like being held back by my advisor, who is agreeing on this situation, my question is: How should I proceed in this case with regard to the division between our leadership? The postdoc will probably perform some of the experiments that took me (a PhD student) two years to find the right track.