There are places for your two different NPI numbers within the system. If you click on Preferences, you will see a blank for "Your NPI" and (under the heading of Practice Group) another blank for "Practice group NPI".
Even if you are the only member of the "group" you will need to fill in all the blanks in the Practice Group information in order to use the Practice group NPI on claims.
There is a confusing situation that often exists; I suspect that you are encountering this difficulty. Many therapists are known to certain insurance companies by their individual NPI, and to other companies by their group NPI. But there is an option in TherapyAppointment.com to deal with this.
If you have your Practice Group information filled in, by default your claims will be completed using the Practice Group NPI in box 33a of the CMS-1500 form, and your individual NPI in box 24J (bottom) of that same form. But if you want to FORCE your individual NPI into box 33a for an insurance company that knows you only by your individual NPI, edit the insurance company information and select that option (near the bottom of the insurance information page). Then all claims GOING TO THIS COMPANY ONLY will ignore your Practice Group information.
Please contact Technical Support if you have additional questions.