Thank you for your posting. There are many groups that seek converts by at least initially telling people that they are a Philosophy of life and can practice their own religion and the new Philosophy side by side. One other group that comes to mind is the Soka Gakki, who tell you that you can chant their mantara and practice your old religion, but slowly isolate you to their group alone.

TM and Yogic courses, as well as some Quasi Buddhist groups will approach and rob you of your faith by slowly engaging you, until they control your life.