I don't have much experience with yeast ranching. That said assuming you took the same precautions as if you had been washing yeast for storage I don't see a problem with dividing the starter up for long term storage. I'd count that as a generation towards the generally accepted 5 generation limit*. Or just decant and send the whole batch through a double round of step ups and use it as is. If you were really concerned with viability you could wash them before stepping back up or storing.
* The 5 generation limit I feel is heavily dependent on sanitation practices, ABV, and the amount of equipment the brewer has invested in being able to determine/count cell viability. If you can plate out healthy/ideal cells there's theoretically no generation limit. Microbiologists and practiced ranchers please correct/educate me if I'm wrong.
1°: Ginger Amber, Blackberry Melomel, Cider; 2°:Orange/Clover blossom mead, Banana wine; Conditioning:Cyser, JAOM, In like a Lion RIS ; Drinking: British Mild, In like a Lion RIS