You might check with GBCI, but the credit language in this case seems general enough that you could get away with the one bike rack in this situation. (Given the credit language "a main building entrance.")

Are the office blocks connected internally? If not, this might be harder to justify. It's also very much worth considering what is best for the project—if offering an additional bike rack will be a good incentive for bicycle commuters.

Our LEEDuser page on this credit has more general guidance.