Dual-Focused

Countless hours have been spent training your mind to maintain focus on concurrent incantations, taxing as the process may be.

• If you attempt to cast a spell that requires concentration while already concentrating on an existing spell, you can maintain concentration on both spells simultaneously. 
• If you take damage during this time, you must make a concentration check for each spell individually.
• At the end of each turn where you have two spells you are concentrating on, you must make a Constitution saving throw (DC = 8 + both spells' levels combined). On a success, you maintain concentration on both spells. On a failure, you lose concentration on both spells.

- Matthew Mercer, Tal'Dorei Campaign Setting, Pg. 108