Suppose I ask a multi-part question, and two different people answer two different parts of my question. Is there a way to accept both answers?
Quick answer: No, this not possible -- if you are ready to accept one of the answers, then use the one that fits your needs.
If there are more possible answers, but none of them addresses the whole bunch of your question, then either the solutions are not totally adequate or your question was too challenging in the sense that there where too many issues to be solved within a single question.
In this case, it is better to split the question. I recommend to post the 'simpler' problem first and when that issue is solved, climb up in complexity, post the next one. I would refrain from post many questions at the same time.
If there is more than one good answer, I hold it for quite natural, to upvote any of them and finally choose one for accept. I would leave a comment on each of those answers not being accepted (or make an edit to the question post), why solution X is preferred over solution Y (Z, ... )