Would the next step simply be to sell enough property to meet the loans plus interest?

Sell en mass to someone else. (That is not easy and most radio companies are in the shitter with no spare money or even equity). It would be a total selloff if it came to that point. Liquidation will NOT meet the obligations they have signed to. You also need to consider that they have other creditors too. This is their biggest one. So there will be a lot of people in line with their hand out.

Z