Hi Andy,
The rocket booster of Cosmos 2777 fragmented on four occassions
into an observed debris cloud of 225 pieces.
See page 320 of -
http://orbitaldebris.jsc.nasa.gov/li...reakupBook.pdf
So if you were observing Cosmos 2227 R/B, which is cataloged
as #22285, then it may have been a debris fragment.
However, if they were diverging, then it would be more likely another
satellite and these types of events happen now and then. For example,
see
http://www.algonet.se/~b_gimle/encountr.htm where Cosmos
1833 and 2227 were observed close together in 1997.