Separation of natural glycosides.

[chemwest]

Hello
I am trying to purify glycosides from natural source. Some of the glycosides are very closely related by mass and its very close on HPLC. Mobile phase used was Acetonitrile - water and 0.1% TFA and Zorbax ODS 5micron column. Some compounds separate while others (larger ones) tail.
Suggestions and ideas welcome for better separation.
Thanks

[unmgvar]

what is the biggest Mw of the compounds?

[chemwest]

According to LC-MS the m/z are 740, 755 and 817.