I agree with @Hal_Al.
Permanent easements qualify for like-kind (Section 1031) exchange treatment but you most likely will simply reduce your basis in the property (hence, no capital gain to defer at this point unless the payment exceeds your baais).
There are also no particular rules that apply as a result of the payment coming from the federal government.
Further, you can split the proceeds in whichever way (in terms of percentage) that the owners decide. The default, however, is a split in accordance with the ownership interests.
