"wheelhouse" is a similar word.
wiktionary
(Canada, US, figurative) A person's area of authority or expertise.
Synonym: domain
Horse viruses are in Pat’s wheelhouse.
dictionary.com
in one’s wheelhouse,
within one’s area of expertise or interest:
There are some subjects that are in your wheelhouse and some that are not.
However, it's usually limited to the preposition "in." You would not say:
politics wheelhouse *
management wheelhouse *
And it's also a somewhat quirky expression that some listeners might not be familiar with.
Putting aside figurative words, there are more standard choices:
"That's their specialization / specialty / area of expertise / domain of expertise / job."
"They are experts / gurus / professionals / very knowledgeable."