5 land titles owned equally by 8 siblings.

We are co owners of 5 land titles that was left by our parents. There are 8 of us in the title and therefore each one owned 1-8 of each lot. We hired an attorney to petition the court to sell all these properties and divide  the money equally among us. The reason for going to court is that two of the siblings think that two particular lot was given to them by our parents through a will that never exist. We underwent mediation and countless court appearance that seem to be going nowhere because the judge can't make up her mind on what ruling she is going to make. Ten years  and counting. Since 6 of us believe that  a solution to sell all these properties as a whole is not possible because the two siblings will not sign any sale documents, I would like to know if six of us can sell our 6/8 shares together without the consent of the two. If we can do that , then how do we determine which part of the land is the 6/8 that we are trying to sell and which is the 2/8 that belong to the two. Let us say that we found a way to identify the 6/8, how do we proceed on selling that 6/8 shares?

Another question is, can I borrow money secured by my 1/8 share of the land without the consent of the other co owners. Or can I sell my 1/8 share? Can I donate my share to charitable intitution if i wanted to. Thanks.