Since this property devolves on all the legal heirs equally, if your sisters want to give away their shares to on of their brothers, they can transfer their share by executing a registered release deed in favor of the brother relinquishing their rights in the property or by executing a registered gift deed or by executing a registered sale deed.
The execution of any of the above deed will not take much time, it is a matter of preparing the document and getting it registered before the registrar's office on the same day.
However since there is no partition deed prepared for partitioning the property among yourselves, it will be hard to identify each individual's share in the property, therefor it is advisable to effect partition among yourselves, and they can transfer their share of property so identified in favor of the brother proposed accordingly.
Further, your sisters need not take permission or consent from their spouses for this act.