In our group (we have 20-something offices) there are a few different nurse roles, although they vary by office and some offices have more than one
resource nurse- phone triage, nursing visits (meds; MAs do immunizations), help w some case management duties, some pt/disease education
case manager- hospital follow up calls, BP checks, diabetes/nutrition/htn/etc education, help w in office meds (b12, testo, depo, etc), more focus on quality/outcomes
offices that don't have a CM have resource nurses that also do hospital follow up calls.
although mas technically aren't allowed to do "triage" they do "screen" low acuity patient calls (cough or rash without other symptoms, nasal congestion, sore throat). MAs also do rooming (vital signs), Rx refills, immunizations, ppd testing/reads, some bp checks/urines/simple nursing visits, and respond to a lot of pt calls/questions that are not high acuity and do not require a nursing degree. coumadin management is either done by the MD, nurse, or an experienced or certified MA (md always 'confirms'/signs off on dosing changes).
we also have some specialty offices with specialty nurses-- in derm, helping with procedures; in rheumatology, doing biologic injections and helping with some of the more complicated results calls
in general, unless you are the person responsible for pt/inrs, the doctors are responsible for their own labwork and imaging results. results letters are generated by the computer (very little work required). we have psr's/secretaries who make the majority of pt appts (unless you are triaging someone and then need to schedule them- then you do it yourself). insurance auths are mostly done by ma's, although sometimes an experienced secretary or nurse will do them as well.
sounds like OP is understaffed- i dont know anyone in our group who fields 60-70 calls a day! i guess i am also lucky in that our group is run pretty well overall and we are afilliated with a major hospital group with arguably the best hospital in the state. we have a robust group of float MAs and secretaries/front desk folks. i am the only full time float nurse at the moment, although hopefully that will change eventually.