  We study the interaction problem of a linear polymer chain, floating in
fractal containers that belong to the three-dimensional Sierpinski gasket (3D
SG) family of fractals, with a surface-adsorbed linear polymer chain. Each
member of the 3D SG fractal family has a fractal impenetrable 2D adsorbing
surface, which appears to be 2D SG fractal. The two-polymer system is modelled
by two mutually crossing self-avoiding walks. By applying the Monte Carlo
Renormalization Group (MCRG) method, we calculate the critical exponents
$\phi$, associated with the number of contacts of the 3D SG floating polymer
chain, and the 2D SG adsorbed polymer chain, for a sequence of SG fractals with
$2\le b\le 40$. Besides, we propose the codimension additivity (CA) argument
formula for $\phi$, and compare its predictions with our reliable set of the
MCRG data. We find that $\phi$ monotonically decreases with increasing $b$,
that is, with increase of the container fractal dimension. Finally, we discuss
the relations between different contact exponents, and analyze their possible
behaviour in the fractal-to-Euclidean crossover region $b\to\infty$.
