Answer:
In RFEM, built-up sections called Castellated Beams are available in the cross-section library. They allow you to place openings in the web of sections such as W-shapes for example. The layout of the openings is parametric where the diameter and spacing can be adjusted. These cross-sections can further be designed in the RF-STEEL AISC add-on module.
You can then set separate cross-sections for the start and end of the member allowing you to create a tapered section.