The 'Start Additional Processes' is a function for team leaders to use. As such, if you have many team members who would all like to be able to start their own processes using this function, you can designate multiple team leaders.
Here is the only thing you must be aware of...team leaders get special notifications. They receive the team invitations if someone sets up a new event an invites your team to address it. They also get notices when you and your team mates fall behind on your tasks.
If you set up multiple team leaders on your team, the team leader that has most longevity on strake/IR (set up first as a user) will receive those notifications. Is it a glitch? Well, in the most traditional uses of a tool like strake/IR, a team leader would delegate processes to their team members to address an event because they are most aware of resource availability.
Recognizing you might want to use strake/IR to run processes without engaging a team leader to start them for you, you can 'dummy' the system and designate multiple team leaders. In that case, strake/IR must make a logical decision about who will get those notifications specific to team leaders...and it has chosen to do it by seniority on the system. Some day that may change if we learn that many of you are creating teams with multiple leaders! So let us hear from you!
Visit this help article to make the change...scroll down to Roles, Step 1.