Voting issues should be addressed in your bylaws so check there first. I suspect your bylaws allow proxy voting and perhaps absentee voting so that is the best way to handle the issue. If your bylaws do not address proxy or absentee voting then you can lean on the permissive wording of the statute (3101 section 4) each time you send out a meeting notice"The call to a meeting may state that an owner may elect in writing to appoint another owner to vote in the owner's stead." So you can easily give the Trustee a chance to determine who will cast the vote for the trust. Templates for absentee and proxy voting can be found under the Resources tab.
The statute does not address the form of parcel ownership so personally I would caution you against using the term "beneficiary" when discussing ownership and voting rights. Determining a beneficiary requires digging into the trust documents and beneficiaries do not necessarily have authority to administer the terms of the trust. Identify parcel owners as required by the statute that states that meeting notices are sent to owners at ".....the addresses set forth in the municipal tax records....." and give owners the voting options as outlined in your bylaws or as mentioned above.