It always helps to verify what's there so something appropriate/compatible could be recommended. Could you take some and upload to the site(?) Then you would post the links to those photos here so we can take a peek.

That said, you should be able to find some distribution systems @ Crutchfield, or at least with photos, determine what you need from some other source online/locally. Examples:

This one handles ten pairs of speakers-

Wall plate for multiple speaker pairs-

I have had luck in the past when I've needed a specific part and wanted quick advice. You can call Crutchfield directly for this sometimes.

I also like the assistance of the expert audiophiles @ AVS forum-

Hope that helps,