Coloured coins to represent indebtedness

[Najska]

Hi,

We know that it's problematic to issue coloured coins to represent equities or shares in a business. I believe this is so not only in the US but also in the majority of the world, since there must be a legal register that binds the coloured coins with the real shares. However, I don't know what happens when Alice lends some money to Bob, and both agree on the fact that a coloured coin represents that loan. So, what if we establish a web of indebtedness, with coloured coins representing a certain amount of money, without having a definite "borrower"? What would be the legal obligations related to that situation?

Basically, what I would like to create is somewhat a SOM (Someone Owes Me).