I work as part of a team that carries out "Function X" (e.g. Quality Assurance Testing the product that team T works on). My team and team T report to the same "Big Boss" senior manager.
As part of a long-standing disagreement (apparently) Senior Manager S who used to be responsible for function X now thinks that it belongs under her remit instead due to perceived deficiencies in the way it's being done currently (e.g. testing isn't thorough enough and too many errors get through the process). S is in charge of delivery to the customer.
In my opinion our team is "underperforming" due to organisational constraints rather than people being incapable.
Senior manager S is now recruiting for people to carry out "function X" reporting to her, essentially setting up a new team to carry out this function. The role being recruited for is the same but differently worded (e.g. "Tester" vs "QA analyst") Recruitment is being done openly, internal and external.
S hasn't discussed with the current team; it's unclear whether it has been discussed between her and the big boss of us and Team T. (If it has, it wouldn't have been amicable!)
I brought it up casually with the Big Boss of our team and team T, and it was dismissed. I think he is unaware of it, rather than "in the know" and allaying fears.
I infer that if this happens, I and my team will be made redundant in favour of the new guys.
Is it a known thing for another area to "usurp" a function?
What steps could I take to secure my position?
Should I start looking elsewhere or is that jumping ship prematurely? (Not sure what I could give as a reason for leaving in an interview!)
(Edited/Added) Why recruit new people rather than redirect the existing people?