Sure. Lets have any pharmacist dispence meds only if he "feels" they are the "correct type". You hoof down to the pharmacy on a doctors orders and it would be a hit or miss if you got your meds.
Not the world I want to live in.
We let kosher delis sell only kosher food...we let Ford dealers only sell Ford cars...we let every kind of retailer under the sun choose what and what not to sell, based on all kinds of criteria including conscience.
Even doctors have the freedom to decide which surgical procedures they will and won't do, based on conscience. Why must we bind the hands of pharmacists?
If pharmacist A won't dispense a certain drug and pharmacist B will, then pharmacist A has ceded part of the drug market to pharmacist B. If there's enough demand for the drug, pharmacist A will have significantly hurt his or her business over it, and pharmacist B will get a significant boost. If the drug in question is so heinous that neither pharmacist will dispense it, then somewhere there is a pharmacist C who will be more than happy to. There's no reason not to let the free market sort this out.