Ok. Here is what you do...
1. for each query with the same criteria, you will reference a form to supply the parameter. For example, you have two queries, one of which updates based on project number and the other on project number and date. your form would have two fields, project number and date.
2. You populate these values on the form and setup a run button. This run button runs the two queries, only they don't require any input from you since the form is already populated with the data they need. To program the run button, you can either create a macro and use the command button wizard or you could do it with VBA.
What vbainet was talking about with hidden forms is a way to run multiple criteria to different forms in the background. I use this quite frequently when creating report launcher interfaces where people will query the same field by their choice of combo box (IE Project number, Project Name, Accounting code all relate to the same project). Although he is different in that he is feeding a hidden subform whilst I am opening up a new hidden form.
***For the query criteria you would put [Forms]![Yourform]![YourFormField]