LONDON — Several alleged victims of tabloid phone hacking in Britain will soon file lawsuits against a second newspaper group, Piers Morgan’s former employer Trinity Mirror PLC, their lawyer said Friday. Mark Lewis said the claims would be filed in “a few weeks,” but would not disclose identities of his clients or say precisely when the papers would be presented at court. Lewis represents the family of Milly Dowler, a 13-year-old girl abducted and murdered by a pedophile in 2002.