Then it seems that we have to use the syntax that you doesn't like very much :-)
```   <tags>
     <tag id="sap_instance_1">
       <obj_ref id="sap1"/>
       <obj_ref id="sap2"/>
       <obj_ref id="sap3"/>
     </tag>
```
Instead of
```
      <tag id="sap_instance_1-sap1" name="sap_instance_1" ref="sap1"/>
      <tag id="sap_instance_1-sap2" name="sap_instance_1" ref="rsc2"/> 
```