Sheet Molding Compounds (SMC) offer a cost efficient way to enhance mechanical properties of a polymer with long discontinuous fibers, while maintaining formability to integrate functions, such as ribs, beads or other structural reinforcements. During SMC manufacturing, fibers remain often in a bundled configuration and the resulting fiber architecture determines part properties. Accurate prediction of this architecture by simulation of flow under consideration of the transient rheology and transient fiber orientations can speed up the development process. In particular, the interaction of bundles is of high significance to predict molding pressures correctly in a direct simulation approach (resolving individual bundles). Thus, this work investigates the short-range lubrication force between fiber bundles with analytical and numerical techniques. A relation between the effective sheared gap between bundles and the absolute gap at the contact point is found and compared to experimental results from literature. Different approaches of implementing the result in contact subroutines are evaluated to enable the use of short-range interaction in a direct bundle simulation framework.