Startegy and Package sequence ( Bit diffrent)

G'Day All ,

We have a unique requirement from our client . Our client does the same preventive maintenance work every 3 weeks , 6 weeks and then 10 weeks .As this sequence  is a legal requirement ( we cant change to 3 week , 6 week , 9 week )

Maintenance packages required for  3 week , 6 week , 10 week . Then 3 week , 6 week , 10 week as so on.

How can we achive this in SAP ? ( attaching a modified screen shot  of what , I would like to achive )

Thanks & Cheers

Frazer