Group Asset solution design questions

We have a number of complex business requirements about our existing assets reconfigurations in Oracle FA (R12): we have about 1000 assets in Oracle FA, they are all independent assets, but as a matter of facts, some of them actually belong to a combined asset, for example, asset 100 is a bus funded by partially federal money, asset 200 is actually the same bus funded partially by state money, we current treat them as two assets. We want to combine them into a "group asset" -- a single bus with two funding sources. Funding sources can be identified by