Ash-Shaykh Mashoor Hasan Aal Salmaan was aasked: Is it permissible for a woman to combine the voluntary prayers of zuhur with the voluntary prayers of ablution with an intention?
Answer: There is no blame, if she does many acts (of worship) with an intention. Especially when busy.
The Prophet sallaLlaahu 'alayhi wa sallam said: If anyone of you thinks of doing any job he should offer a two rak`ah prayer other than the compulsory ones (Collected by Al-Bukhaaree).
What do you call these two units of prayer?
(They are called salaah Al-Istikhaarah).
For example; The sunnah after zuhur and the prayer of istikhaarah. There is no harm in this.
I have found Imaam An-Nawaawee in his introduction of his book "Al Majmoo'" saying: I was asked about the issue of praying two voluntary prayers for many purposes with an intention. I then pondered on it for over twenty years and I answered: I hope there is no blame in it.
There is no blame in it bi idhniLlaah.
Majlis Al-Fataawa Al Jumu'ah
Muharram 18,1440 A. H.