Hi
the seller sold his land to two different persons
that sale happened without any partition on record. Though buyer parties by their acts acted upon a virtual partition such that each agreed to take possession of the agreed portion of the land
that is, you agreed to be in possession of road side portion and your co-owner agreed to be in possession of the rear side portion of land
now the moot question is that though the buyer parties agreed in the sale deed as to what portions of the sold land they will occupy, both parties paid the sale price in EQUAL proportions
generally the road side portion should be costlier than the rear side
but in your case it is nobody's case that you have paid anything extra for the road side portion. In fact admittedly both parties have paid equally
had you paid a higher sum than your co-owner, you would be of right entitled to say that the road side portion is exclusively yours and therefore if any portion of that land is being acquired then you alone would be entitled to entire compensation
but such is not the case
on the flip side, you can say that your co-owner waived his right to pay lesser for the rear side portion and chose to pay equally (ideally he should have paid less as the portion of land being given to him was of lesser value being on rearside) and now he is estopped to say that since he paid equally, he has any right over the portion of the land which is in your occupation. If the co-owner paid more then it was at his peril and he cannot take advantage of that fact and now claim compensation for the portion of land which is in your occupation
hope i have been able to explain