Is this allowed? In theory and practice, yes, there are many mechanisms which would allow you to do it.
Is it ethical? It depends on perception.
In my opinion, this qualifies as "salami slicing", i.e. cutting up results to generate more papers. Now if you published one method, then discovered the other method is either better or worse and published it afterwards, that is just the progress of research.
However, and this is my opinion, grounded in my personal ethics for publications, what you are doing is unethical. You currently have both studies which together could form a more concrete and informative publication, yet you are deliberately choosing to split them, presumably to generate two, less-informative publications.
The good news is that my opinion, and those who share it will merely earn you an eye roll and less respect in the community. So really, what's that worth to you in the end?