I want to increment a cell reference of a formula

I have a sheet with player names that change every 19 rows and I want to be able to quickly drag the row down and have it auto paste the formula with it adding 19 rows and pasting the data in for that row.

"Sheet 1"

B2 - =Sheet2!B2B3 - =Sheet2!B21

and I want to drag the formula in B2 down as many times and it makes the formula essentially,

B29 - =Sheet2!B517

I've attached a sample sheet for reference.

https://docs.google.com/spreadsheets/d/1tyJfjO5tErGSPBQaLswagHCy8mhJf7m9QM7ZJyU2I68/edit?usp=sharing

Are there any formulas I can plug in or shortcuts to use and cut down the time by not having to manually add 19?

Thank you