Citi runs most of the non bank/amex affiliated cards. As you have mentioned, think Coles, Woolworths, Virgin Money, Qantas - all not financial institutions.
I have heard of Chase cards in US implementing a 5/24 rule, which means no more than 5 Chase cards in 24 mths. Citi in US has a 24 mth per card rule.
In Australia, I have heard of having to wait 5-9 mths between Citi applications. Nothing official, just word from forums and websites.