IDoc Packaging from XI/PI to SAP instance - possible?

Hello,

I'm looking for a way to package IDocs into a single tRFC call from XI/PI to a SAP instance, has anyone done something similar previously? So far all I've been able to find are solutions for the IDoc Sender Adapter (SAP to XI/PI).

Messages are sent into PI via the XI protocol one at a time, then mapped and sent to an SAP instance - I do not want to introduce ccBPM into my scenario and we are not at a sufficent SP level to use message packaging. Any ideas?

Many thanks,

- Ian