Pls help accounting rules for inter company transactions

Yes inter company transfer is a possible transaction. It can be just fund movement or purchase or sale.

In case of  your example what might happen is , there is one company making purchases on behalf of other, in such a case one can make the party receiving benefit from other be grouped under "Sundry Debtors."

Example : ASS is a subsidiary of MTA. MTA holds ASS & GWE. GWE makes purchases.

In books of GWE :

Purchases

       To Suppliers

(When goods are purchased)

When goods are sent to other group of company's

Party's a/c

         To sales