Hello,

InfoPath automatically stops you submitting unless all fields are valid.  It
will give you a nasty message box to tell you off as well :)  The real trick
is getting it to submit with invalid data... which can be done, but isn't
pleasant.

So basically, add validation to your fields, and InfoPath will automatically
not allow the user to submit unless all fields are valid.

HTH

Gavin.

Hey Eric.

I think what you are referring to is performing your own checks and adding
multiple rules to the submit button.
By default the submit options are to perform one data connection to submit.  
What you need to do is change the drop down to rules based. Add your rules
and then at the end add a rule to submit to the data connection you need or
multiple submits.
So tools
Submit Options
Rules based
Add Rules
Set your button to submit