Approvals for Transfer Order

Project currently needs approval on Transfer Orders, so we wanted to use Internal Material Transfer requisition (IMT req), once that is approved Transfer orders will be created. 
However as per Entp. structure that caters Client need, we have 1 inventory Orgs associated to 1 BU, as of now total 30 org and 30 BU.
But, Assigned Business function for requisitioning for them is disabled , except for 1 BU. This one req. BU raises PO for all the inv org in different BU meaning destination or SOLD to LE will be of receiving org., 
(location should be mapped to Inv org to default sold to LE on PO)