Hello- We have a small dog that is getting to be around middle aged, and were thinking about looking into replacing a portion of the metail rail at the top of our staircase with a half wall. I was curious if it would be possible to build a frame over the existing metal rail without having to take the rail out. We would also be interested in having a permanent baby gate, possibly one that could slide in and out at the top of the staircase to keep our dog from running/jumping downstairs. Any thoughts would be appreciated! Thanks!