This call of OP is a call that can never happen, for as long as we have people without conscience, it is only conscience that can prick the dumpers and push them to make a reasonable move as regards their dumping of token, but since money is involve, the God of mammon would not allow them to think straight.
Whenever people sell huge amount of coins/ tokens, price will be dumped, whoever sell those coins/ tokens. No one can control such dumps.
Projects are unable to grow if they can not release good products, good use cases.
So, the best way to just handle this is for developers to continue working hard to build the project, if they have a real product with use case, no matter the dumping that has occurred, there will always be opportunities to get investors or users that will continuously place demand on the remaining token which will turn the table round and make the value starts to grow again, then they also need to reduce the amount of token they give as interest.