If the OP is really referring to 3Com 5500 Switch family (in particular to 3Com SuperStack 4 Switch 5500-EI or 3Com SuperStack 4 Switch 5500G-EI, HP equivalent E5500 Switch series is here)...well...that (old) 3Com family - AFAIK - wasn't Comware based (probably Comware wasn't born at time...but I could be wrong about this detail) nor is it actually possible to (re)brand them from 3Com to H3C to HP/HPE (reference here)...so Comware IRF (Intelligent Resilient Framework) technology isn't supported at all (note that, instead, IRF is available on the HP 5500 EI Switch Series we know also as HP A5500, derived by H3C S5500-EI Switch Series derived initially from 3Com Switch 4800G).
That 3Com SuperStack 4 family, instead, supports 3Com XRN (eXpandable Resilient Networking) technology which was the technology foundation from which IRF was initially introduced and later developed in the H3C/HP era.
Hope not be wrong...
So instead of an IRF Stack those 3Com SuperStack 4 5500-EI/5500G-EI can form an XRN Distributed Fabric (up to 8 units and loop only topology).
Various references here (manuals and software) and here.
3Com SuperStack 4 5500-EI models use (last two) front facing SFP ports to create the XRN Distributed Fabric, 3Com SuperStack 4 5500G-EI models use a built-in dedicated fabric back facing special stackign ports (Yellow: Uplink | Cyan: Downlink) necessitating of dedicated 3Com special stacking cables.
To create an XRN Stacking Fabric see Chapter 4 of this getting started guide.