Shimano and SRAM 10-speed cassettes use the same spacing, so the wheel with the 28-tooth big cog would probably work fine on both bikes. You might need to adjust chain length. And you might need to adjust the rear derailleur a bit to account for any slight spacing differences of the wheel/hub.
If you were putting the 32-tooth cog on the other bike, you'd need to make sure the derailleur could handle the larger cog.
If you don't want to worry about chain length and derailleur capacity, you could simply swap cassettes temporarily. You still may need to fine-tune your derailleur.
Last edited by SkyDog75; 07-05-14 at 11:15 PM.