YES

3 decompositions
 #1 -----------
   1: F(x2,x1) -> c(x1)

 #2 -----------
   2: G(x2) -> x2

 #3 -----------
   3: f(x2) -> g(x2)
   4: g(x2) -> c(x2)

@Jouannaud and Kirchner's criterion
--- R
   1: F(x2,x1) -> c(x1)

--- S
   1: F(x2,x1) -> c(x1)


@Jouannaud and Kirchner's criterion
--- R
   2: G(x2) -> x2

--- S
   2: G(x2) -> x2


@Jouannaud and Kirchner's criterion
--- R
   3: f(x2) -> g(x2)
   4: g(x2) -> c(x2)

--- S
   3: f(x2) -> g(x2)
   4: g(x2) -> c(x2)