Hi @JESSICAPRIESTLE ,
@Gabriel33 is pretty much correct. Unfortunately, there is no current feature inside of Canvas that allows you to assign specific items inside of modules to specific groups. This also applies to modules as a whole. Groups are used so students can work together and collaborate on an assignment, and then only one student has to submit the assignment for the entire group, and in the gradebook after that one student submits that assignment, it will mark it off for every student in the same group as them.
That being said, there are two ways you could go about this. One, would be to specifically assign individual students to assignment (which could be very time consuming given the fact you have 90+ students in your course), or, and from what Gabriel said before, you would have to divide your students into different sections in order for this to work. However, with many institutions, especially if your Canvas was set-up using a SIS import, this can easily disrupt the intended functionality when it comes to syncing grades and other information from Canvas back over to your SIS, which is why most schools do not allow teachers or TAs to edit their course sections. However, if you do not have a student information system connected to your instance, or if your course is a manually created course which also allows you to edit or create sections without anything being interrupted when it comes to syncing with your SIS, this might be something you could do! However, keep in mind that these students will always be in the same section ("group") unless you take the time to change it, which means they will be working on the same "group" assignments for the rest of the year.
I hope this additional information assists you!
Noah