Well, the answer depends on what business means to you and how can you ensure that you will not be able to mix different businesses on single invoice. 

In IFS system you can connect invoice serie to branch (connected with site) or numeration group (connected to customer) within invoice type, perhaps it could help...

I would use this as reporting purposes to separate Service business invoices from the Equipment business. Now when the invoice series is the same for both of the business i have to pick only based on amount of the invoices like < 100KEUR invoices are for Service Business and higher tahn 100KEUR for the Equipment Business. This will not give right assumptions every time.

 Our SITE is same for both of the Business > cant use that to separate

and also numeration group based on customer cannot be used because we invoice the customer both businesses .

I read your message again and you say something about Branches that can be connected to SITE...i’m not familiar with that...perhaps i need to check what that means and if that can be used somehow.

thanks,

Sami

If your site is same and customers are same - neither branch (attribute of site) nor numeration group (attribute of customer) will help you. But the question remains - how your invoicing process can ensure you are not mixing both businesses in same invoice? 

My suggestion would be to use separate sites...

Both Equipment and Service are different profit centers and invoices are created by different employees. Equipm and Service invoices are never included  in the same invoice.

SAP automatically split the payment as per ratio of vendor invoice and this is example of Passive Split. 2.2. Active Splitting. SAP split the line items of some pre-defined splitting rules. ... Customer etc.) Splitting Method are pre-defined by SAP .In order to implement document splitting following elements need to be configure .

Well, in such a case profit center should be a part of invoice accounting key (code part value of some code part) for reporting purpose - or service business should be managed from separate site(s). One or the other should have been considered during IFS system implementation - ERP solution must gather all the information needed for reporting purposes. During lifetime of the system changing accounting key could be problematic, introduction of new site requires setup effort as well - is your reporting need important enough to justify the effort?