Assembly Constraints vs Analysis Constraints

[TheJMartin]

I'm using Inventor 2014, unfortunately I cannot share my models due to company policy.

I have a box held together with screws that is affixed to a floor using more screws.  The assembly constraints are all messed up from the last person who attempted to perform my job, and I'm trying to figure out if I can skip the "fix every single screw step" by constraining pieces of the box using frictionless (?) constraints on the bearing surfaces shared between parts.  I understand that neglecting fasteners in simulations is common to reduce calculation time, and I'm hoping there's an accepted way to perform this in Inventor. 

If I impart a force to the box, what would be the best way to constrain the reaction of screws in shear and tension while neglecting the fastener itself?

Thank you.