We can probably consider combination, if we know like this:
http://www.simillimum.com/Thelittlel...wscholten.html
There can be various types of remedies. Energized, elemental, single molecular, bi-molecular, multiple molecular, inorganic based, organic based etc. Although, it may be possible to combines (as bio-combinations) & use, provided chemical compositions of all remedies used in combination are previously known & understood, homeopathically, BUT still specific proving of whatever we are taking should be the true justification.