We currently have a legacy (home grown) survey tool that has nearly 100 questions. Though we have been able to separate them by groups, I was wondering if it would be possible to "chain" smaller surveys. This way, an admin can mix and match smaller surveys to fit the individual needs.

I would recommend to have a single survey with tokens but a respondent will only see some of the groups, depending on some variables that you upload in the tokens table.

You can even go as far as to allow to choose the respondents the groups they want to reply to.

Chaining surveys is not impossible. You can set a link at the end of the questionnaire (Edit text elements --> End URL) and then make it auto-load at the end of the questionnaire (General settings --> Presentation & navigation --> Automatically load URL when survey complete? = YES).

But this would be static, and you wanna mix and match. Truth be told, you should be able to study how placeholders work in LS, then insert a placeholder instead of the study number in the end link that would call the number from the tokens table. But I really think there are not many occasions when you want to do this. Especially since you need to do this for all surveys...

It's definitely possible to chain them together as @atiut described, using the end survey url. I like this approach because it gives you three levels of hierarchy -- "super survey", survey, and group. But ideally you need to create a front end that ties the surveys together and keeps track of which are finished, etc., which isn't a trivial project.