Query regarding transmission of shares and actual legal rule

For a leading company we had sent shares for transmission to legal heirs. There are 3 legal heirs and even as per succession certificate all three are named legal heirs. But in transmission form we had changed the order 

The succession certificate is ordered as follows

1. a
2. b
3. c

But in transmission form we have asked transmission of shares as follows

1. c
2. a
3. b

mainly because the demat account is in that order.

Now all companies except this has done and rejected reasons says order of legal heirs does not match and when i contacted the transfer agent they say its as per rules it is only allowed to be transmitted in this order.

So is there really such a rule? If so can someone guide the exact section/rule? And if that was the case how did all other companies transmit the shares in the order as per transmission form 

Because all legal heir names match the succession certificate names just the order is different.

Is it just a way to delay transmission of shares?