Ram Frame Wall Base Lateral Foundation Spring

I'm trying to capture the effects of a lateral foundation spring below a concrete core wall.  The foundation spring for wall bases in Ram Frame is a vertical spring only.  In my current project, i have (2) levels of below grade and the concrete core is on drilled piers.  We would like to determine what the effects are on the coupling moment between the subterranean slabs when lateral foundation springs are introduced, so the concrete wall base is not acting as a fully restrained condition, as is the current default.  Is there a way to accomplish this?