Hi Kumar,
I don't believe that you need to load GL TEXT into the infocube. It is better to create two flat files from one. One flat file consisting of just GL Account and GL Text and another consisting of GL account key, company code and period. It is not advisible to load text into the infocube. Load the GL Account and GL Text into the infoobject GL Account as text data, and load the other flat file into your infocube.
Then based on the GL Account ID as common create the multiprovider and choose the infoobjects from the relavent infocubes by characteristics Identification. Please rephrase your question regarding usage of the multiprovider as it is hard to know what data you are planning to merge using a Multiprovider.
Regards,
Manohar. D