You can make your own cages from wood & meshing to separate two boars with a common wall. See the outdoor idea & C&C pages for more ideas.

Above: Karen's set up allows her single boars to interact with each other through the mesh but prevents the fur from flying as her boys do not get on. Karen tends to re home single boars who won't accept company & this set-up allows them to enjoy piggy company in safety.

Above: This is a variation on the C&C cage using wood instead of correx.

However if your DIY skill are lacking putting 2 indoor wire top/plastic base piggy cages side by side works almost as well. Janets Set up (above) show this. Piggy's can come up to the bars & see each other yet not get their teeth & claws far enough through the bars to hurt each other. The plastic base however prevents them from snuggling up in the way they can in a C&C or mesh to the floor design. Perfect as a temporary solution though if you are hoping your piggy's will get on together in the end up.