release deed is not necessary as you have been authorised by your sisters to sell the property by POA 

Please be aware that the share certificate given by the society is not a title document.

The property belonged to the deceased owner who is reported to have died intestate, hence it shall devolve equally on the deceased owner's legal heirs.

Now some of the legal heirs who reside in a foreign country have executed a POA in favor of the Indian legal heir, the power agent can sell the property on behalf of them also without insisting a relinquishment deed from them, he can combine the local residents as parties to the sale deed that is to be registered in favor of the prospective buyer. 

On the basis of POA, you can sell the property, you are duly authorize to act on their behalf. And about distribution of payment, all have 20%. You can retain the full amount with their consent or if you are authorize through POA.

1. Transfer of Society membership is NOT equal to Transfer of Property.  IT is just simply transfer of Society's Membership in Five persons names.

2. You can sell the property by mutual and joint signatures of all Five persons in the Sale Deed, as  "Confirming & Consenting Parties".  This will not require any further documentations etc....

3. IF point no. 2, is not feasible, THEN execute a Registered Family Settlement Deed in favor of one person, who can then sell the property on behalf of all others.

Not necessary, A POA will authorize you to sell the property.

You can sell ancestral property with the consent of all legal heirs. You sisters can execute Registered POA through Consulate.

You may have to authorise the power agent through this GPA deed to do all such specified acts as mentioned i the schedule of the said deed. 

If the power agent is authorised to do all the desired acts, i the deed with specific mention about them in the deed, then the agent can proceed with such things on behalf of the principals.

It is advisable to have specific POA to sell ancestral property in Gujarat 

1. POA is always given for specific purposes. Hence POA MUST mention the specific details for what & which all purposes alongwith the time limit, non-transfer'bility , the POA maker wishes that the POA holder must act on his behalf.

2. The Registrar of Sub-Assurances, will look into the above, before allowing  any further registrations.

See using there power of attorney you can sell and execute sell deed on behalf of your sisters and the consideration amount can be credited to there account. Release deed to sell is not required. 

See for same POA need to be perused to make a sale deed the power of sale should be there in POA and description of property should be there. 

Depends on language of POA, how much and on which properties, authority given to you. If POA speaks to act on their behalf on all father or fore father or bank accounts n FDs of father. You can .

You don't have to prepare relinquishment deed you all can execute sale deed and transfer the property

The POA should contain the details of property to be sold by the Attorney with clear authorization to do so.  

1. Since you have been authorised by your sisters to sell the property for and on their behalf you do not require any release deed from them.

2. You are bound to share the sale consideration with your sisters unless they relinquish their share therein.

3. For the other property you should get a separate GPA.

1. If you have POA of all your sisters then you don't need to execute release deed in your favour to sell the flat.

2. You just have to get the POA registered with sub registrar to execute sale of flat.