In ZMI, customize the member_search_results to change this expression:

results python:here.member_catalog(request);

to this:

results python:here.member_catalog(request, sort_on=’getCompany’);

getCompany is an index on the member_catalog that was autogenerated by virtue of “company”’s index=’ZCTextIndex|schema’ property in the custom schema of my CMFMember-based product.