Baby Gate for Iron Railings? -- Good Questions

Q: My wife and I are expecting twins in January so we are already starting to get everything ready. One problem I've run into is a baby gate for the stairway. We have iron railings and everything I've found is for standard wooden posts, or a stairway with walls on either side. Any good solutions out there for iron railings, or even a DIY method to attach a standard gate? Thanks!