The easiest thing to do is to ignore bolted connections. In Creo Simulate if two surfaces are coincident with each other they will be connected and displacements will be continuous across the boundary (see Assembly Basics). If you choose this method and ignore the bolted connection the only way to estimate bolt load is to look at the stresses in the parent parts near the bolted area. Based on the stress and the cross-section area you may be able to estimate some ballpark bolt load numbers. This method would only be recommended if the bolts are very closely spaced (less than 2 bolt diameters) and the joint was very rigid.