CLient access and word document merges

CLient access and word document merges

Hi
I think this looks terrific - as a former user of salesforce it looks just as good.
If I want to have certain clients look at their own leads (we are mortgage brokers) can we securely ensure that they are only able to look at their own records?
Also, can we set up word document template merges so we can send personalised letters as well as emails?

Thanks.
Joao Costa