Half the family wants to sell their share of a tenancy in common property.

We cannot afford the price they want to sell for so we have decided to sell our shares too at the same time.

It is a fairly large piece of land.

Should we try to divide/ partition the land before we sell?

We were also considering Leasing the land. Can we lease the whole property and

Share the lease proceeds with the family members who want to Sell? Or the owner who purchases their shares?

Laws on some of this may vary by state.
There is no reason to divide the land if you all are agreeing to sell. It is very expensive for a formal survey and separate deeds, not to mention permission from possible zoning depts! Even worse, how do you decide who gets what actual land parcel? Far too complicated. You could cut down on costs by having just 2 groups, one of which keeps their part of the land and one of which sells. But again, you have both expense and a complicated property line to draw.

Family who don't want to sell can refuse until such time as those who do want to sell to file in court to force the sale by partition. Until the court rules, no one can force a family member to do anything.
“Partition in kind” is an actual division of the property. “Partition by sale” is selling the entire property and dividing the proceeds equitably among the owners. However, before forcing an unwanted sale, the court can permit 1 or more of the co-owners to purchase the interest of the remaining co-owner(s) for fair market value.

This situation sounds like it would do best if you hire a RE lawyer, maybe 2, if there are 2 groups in disagreement. Try your best to agree to somethings to save on hourly charges.

Lease? Of course. It's your land, once probate and who owns what is all settled. But you can't lease or do anything if not. No, you can't just lease and force those who want to sell to accept rents. And you can't sell 'shares' that aren't actual separate deeds, and as I said, that gets expensive.

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This situation sounds like it would do best if you hire a RE lawyer, maybe 2, if there are 2 groups in disagreement. Try your best to agree to somethings to save on hourly charges.

Lease? Of course. It's your land, once probate and who owns what is all settled. But you can't lease or do anything if not. No, you can't just lease and force those who want to sell to accept rents. And you can't sell 'shares' that aren't actual separate deeds, and as I said, that gets expensive.

By "RE lawyer", Joypulv means an attorney who practices real estate law.

I disagree with the assertion that OP, as an owner of an undivided interest in the land, cannot rent or lease the property to a third party. OP could, with the duty to share the rents with the co-owner, and subject to the possibility that the co-owner might bring an action for partition.

But, as noted, OP should hire an attorney to straighten-out this situation.

Another possibility is to sell the land to corporate entity. Those who want to sell can sell their shares in the corporation. Or the corporation can then lease the land to someone and share the lease payments to all shareholders.