  In this paper, we prove a combination theorem for a relatively acylindrical
graph of relatively hyperbolic groups (Theorem 1.1). Here, we are extending the
technique of [Tom21] and constructing Bowditch boundary of the fundamental
group of graph of groups. Suppose G(Y) is a graph of relatively hyperbolic
groups such that edge groups are relatively quasi-convex in adjacent vertex
groups. Also, assume that the fundamental group of G(Y) is relatively
hyperbolic. Then we show that the edge groups of G(Y) have finite relative
height (Definition 1.5) if and only if they are relatively quasi-convex
(Theorem 1.6). In the last section, we give an application.
