If groups/bands can break up and begin to work solo, can solo artists make up a band?

[Ceiling Cat]

I'm talking any band in particular, for example N-Dubz broke up and each of them became solo artists. If there are, say four random solo artists, can they become a band or group?

If there are any rock bands like this then please suggest them?

Thanks, I've been muddled with this question for a while..