Welcome to the community, @Francis_Carbone!
Unfortunately, Airtable has given us no programmatic access to those values in the summary bar, which is a real bummer for everyone who uses Airtable.
Your only native option is to create another table, and then create a record which links to all the records that you want to summarize, and then create a rollup field that summarizes all the linked records.
There are some ways to automate this to make it easier, such as automating the linking from the first table (instead of the 2nd table).
Other non-native solutions include:
- Writing a custom script.
- Using an external automation tool such as Zapier or Make.com.