You can create separate line in each box.

The first line will be for the amount taxable on the federal return.  No special coding required.

The second line will be for the amount taxable to the first state.  Source it to that state and code it with an S, so that it will only be reported on that first state's return.

The third line will be for the amount taxable to the second state.  Similarly, source it to that second date and code it with an S.

If you are not familiar with this type of entries, take a look at this article:

https://proconnect.intuit.com/support/en-us/help-article/multi-state-taxes/entering-multi-state-amou...