I know exactly what you mean having used ANSYS myself. Now, I don't believe there is anything equivalent to this functionality however, if you try applying a mesh control to the edge and decrease the element ratio, this should increase the mesh density on the face of plate B where it comes into contact with plate A.
You can split plate B (intersection split line command) so that they share a common edge. A mesh control applied to such and edge will propagate to both faces with an appropriate growth ratio as mentioned above.
Thanks for the suggestions. Do these techniques work when simulating the plates as sheetmetal shells? I was able to get local density to increase on a simplified sample assembly when the plates were analyzed as solids, but the increased density did not carry over when I analyzed as sheetmetal shells.
Also, Bill, I assume you were talking about the Split Line tool? That tool does not appear to be available in the assembly model. It looks as though I'd have to manually create the split within each individual part? Is there any way to split surfaces within the assembly? I am working with a large multi-faceted sheetmetal tank that has many gussets and connections, and it isn't going to be feasible to create split lines manually within each component.