TRANSAMERICA <TA> UNIT BUYS REINSURANCE UNIT Transamerica Insurance Group, the main property-liability insurance operation of Transamerica Corp, said it signed a definitive agreement to acquire a newly-formed insurer, Commerical Risk Underwriters Insurance Co, from <Clarendon Group Ltd>. Transamerica said the unit, which will be renamed Transamerica Reinsurance Co, will initially be capitalized at about 185 mln dlrs. Transamerica said the acquisition represents its first move into specialty treaty reinsurance. The company said about 28 members of Clarendon will join Transamerica as part of the acquisition, which is expected to close in November and is subject to various regulatory approvals.