That’s no problem haha.
It’s definitely possible to set up a material like that, but essentially the “mud” is a slightly different version of the dirt texture and i think adding in a whole nother layer for it may cause problems if all of the materials overlap in one sector as a single sector can only display 16 texture lookups at once. My recommendation would be too simply paint the puddles layer on top of the dirt at a very low strength like 0.05 or 0.1 to make the dirt wet like mud 
Give that a try and let me know how you like it!