You've added an example in doctors, actually. If a GP has cancer, he or she will go see an oncologist instead of just going on dimly recalled med school courses. The oncologist will see a sports physician about the shoulder injury from rugby, the sports physician sees an opthamologist about their slight ocular degeneration and so on and so forth.

Law is a sufficiently large field (remember, the problem domain is "all interactions between humans") that it requires specialisation and so, in fact, lawyers must frequently consult with other lawyers. OP may get an answer from a general practice solicitor. Or that lawyer may need to consult another lawyer. Until he or she sees a lawyer it's not clear to us lay folk.

Does this ever annoy you?

    You're good with computers, can you make a poster for me?

It annoys me (well, these days I find it funny). Special subjects require specialists.