Juniper MX - Shared layer 3 interface across several physical ports

Hey,

Quick question, for anyone experienced with similar setups in the Junos MX environment,

So what I want to do is create a layer 3 interface between 2 or more physical trunk ports, but I am unsure how to set this up in Junos. The point is to have a specified VLAN-id shared between two layer 2 links, which in turn also have several other VLANs and layer 3 units bound to them.

In the Brocade MLX type routers, this would be done by simply creating a VLAN, tagging the respective physical ports, and specifying a router-interface (ve XXX) to the VLAN itself, which in turn combines both layer 2 and 3 across the specified physical ports.

How would one be best off implementing this in Junos - IRB, virtual switch, routing-instance?
Any input appreciated,