Tier 1 Dependent Maintenance Requirement - Urgent

[gupta.manish82]

I have a valid Tier 1 General Visa and now wish to apply for my wife and my daughter Visa as dependents.
For the maintenance funds I am showing 2 Bank's statements. (followed all the requirements of the statements)

I wish to know the following:
a. I have one Bank saving account joint with my father. Is it ok to show Maintenance Funds from a joint account with someone else other than the dependents?
b. I have other Bank saving account joint with my wife's father and wife's mother. Is it ok?

The crux is that on both the saving accounts I have a joint account but not with my dependents. Can I show these accounts for Maintenance Funds for my dependents.

Total balance I have in these accounts amounts to 8500 GBP. I am required to show 6000 GBP.
I have also got required statements & minimum balance certificates for last 6 months for both the accounts.

Your advice is highly appreciated.
Thanks in advance..