You could alternate the days you take each vitamin. One day take the reccomended dose of Elevit, the next day take the recommended dose of the Blackmores, so on and so forth.

I have taken blackmore breasfeeding gold which is 2 caps once day, I have also been taking fefol which contains iron and folate intermittenly during this PG in an attempted to keep my iron up as I became deficant by the third trimester during my last PG