Hi @london,
Yes, you can filter a roadmap using any layout (timeline, board, or grid). There is a "Search or filter" bar that appears at the top of all the layouts. Use the bar to search or filter for roadmap items by name or ID. You can also select from the available filtering criteria. I don't think the filter is configurable at this point but let me verify that.
You can refer to the following roadmap documentation:
Top-Down Planning with Roadmaps (CA PPM 15.4.1 SaaS)
Navigate to the heading: Apply Search Filters for Roadmaps and Roadmap Items
Hope this helps.
Thanks, Sarmistha