We define a class of topological A-models on a collection of Riemann surfaces, whose boundaries are sewn together along the seams. The target spaces for the Riemann surfaces are the Grassmannians Gr mi,n with the common value of n, and the boundary conditions at the seams demand that the spaces C mi ⊂ C n present the orthogonal decomposition of C n . The whole construction is a quantum field theory (QFT) interpretation of a part of Khovanov's categorification of the sl(3) HOMFLY polynomial.