It is not possible to connect multiple Instagram Pixels to the UpStackified Shopify app. Instagram only allows one pixel per ad account, and since Instagram advertising is managed through Facebook Ads Manager, this limitation applies to the Facebook Pixel as well.
However, if you have multiple ad accounts in your Facebook Business Manager, you can connect a different Facebook Pixel to each ad account and then connect those ad accounts to the UpStackified app. To do this, follow the steps in my previous answer on how to connect your Facebook Pixel to the UpStackified app and repeat them for each ad account you want to connect.
Note that you can also create custom conversions in your Facebook Ads Manager and use them to track different events on your website. This can be a useful workaround if you need to track different types of events for different Instagram accounts. To create a custom conversion, navigate to the "Events Manager" section in your Facebook Ads Manager, click on "Custom Conversions," and follow the prompts to set up your conversion. Once your custom conversion is set up, you can use it to track events on your website and create targeted Instagram ads