There is hereby created a Zoning Board of Review, hereafter called the "Board." The Board shall consist of five members, each to hold office for the term of five years; provided, however, that the original appointments shall be made for terms of one, two, three, four, and five years, respectively. The Board shall also include two alternates to be designated as the first and second alternate members, each for one-year terms. Alternate members shall sit and may actively participate in hearings. The first alternate shall vote if a member of the Board is unable to serve at a hearing and the second shall vote if two members of the Board are unable to serve at a hearing. In the absence of the first alternate member, the second alternate member shall serve in the position of the first alternate. No member or alternate may vote on any matter before the Board unless they have attended all hearings concerning that matter.