How to Extract Shared Parent member name for a member in a shared hierarchy

@Parent

We have an alternate shared hierarchy in the Account dimension. We want to extract the shared parent member name for a given Account in the alternate shared hierarchy.

I know the @Parent function gives the Parent member name from the main hierarchy in the dimension. But, I want to extract the shared parent member name from the alternate shared hierarchy for a member. What function can I use to get this shared parent member name.