I think with most bands, it really takes time. Nick and Neil had been there since day one, Mark for numerous years (and as Mark will tell you it took awhile before he was 'fully' in the band...especially around the Tim joining era).
I think the main hinderance around Peter Jones being in Crowded House is that his time with the band wasn't all that long and especially around studio work.
In the end he was part of Crowded House, their drummer with the blessing from Hessie (could he of asked for a better reference?)
Gryph