I will be honest with you, and say that I had not heard of this (cult like) idea until I purchased two dictionary's of theological terms.. but I have learned that seemingly nothing good came out of the 1800's in American Theology...
A theological movement originating in Tennessee in the Mid-nineteenth century, holding that only Baptist Churches are true churches, that baptism is only valid when administered by a Baptist Congregation and that communion is to be restricted to the members of a particular congregation, for there is no such thing as the universal church. Landmarkism also hold that there is an uninterrupted line of succession of true Baptists, linking the present-day congregations with Jesus and the apostles. In order to show this, Landmarkist historians seek to reinstate many in the past whom the church at large considered heretics, and whose views are now reinterpreted in order to bring them in line with Baptist teachings.[From Essential Theological Terms, Justo Gonzalez].
So what we have is a group of Baptists, who now Join the ranks of The Roman Catholics and the Eastern Orthodox churches to have Succession (Though they call it church succession, as opposed to Apostolic succession) . But they also take on the classic American Cult Mantra --- Unless you are one of US you can't be saved. (Jehovah's Witness', Mormons, perhaps even SDA's fall into this [not all of them mind you] All American, all abhorrent).
Well that is your Term of the Day. Enjoy!