It would probably be difficult to separate those compounds by TLC due to their similarity in structure and the choice limitations one has with TLC as well as collecting the sample once it has seperated. A similar technique would be liquid chromatography. Packing the column with an appropriate stationary phase (most often silica gel) and using an appropriate mobile phase the compounds might seperate.
The mobile phase choice will depend on the polarity of your compounds. Since they are diazo compounds they are fairly polar. If you have acetonitrile you could try a mobile phase of 70:30 acetonitrile/water. If you want to increase the speed of the separation the column can be pressurized. Depending the the separation you will have to change the mobile phase polarity by switching solvents or changing the percentages. Most likely the mobile phase will have to become less polar to encourage the isomers to spend more time in the stationary phase.
If the compounds are too close in nature it will be difficult to separate them without using more complicated High Performance LC equipment.