ISG2000 to SRX3600 Help (with mroute)

Morning Guys,

Undergoing a transition from ISG2000 environment to the SRX3600 environment and am encountering a bit of a hiccup.  In our existing ISG world we have about 20 entries similar to the following.

set mroute mgroup 239.X.X.1 source 10.10.10.10 iif aggregate3.205 oif aggregate5 out-group 239.X.X.1

I cannot for the life of me find a "SRX Equivalent".  Anybody have any suggestions?  I tried searching the forums and help docs, but never really made any progress.

Thanks,

Tyler.