CLX ART with 2 sub connections

I have a stupid question. I’ve heard great things about the Martin Logan CLX Art and wanted to invest in a pair. But upon looking at the connectors in the back of the speakers, I see no connection to external subwoofers. I read that they have some sort of “custom filters” I can get to hook up to a pair of descent i or the balanced force. Yet, I see no speaker wire connections to the subs (they only take RCA or XLR). So how do you go about hooking up a pair of subs to the CLX Art? Thanks!