Śiva Saṅkalpa Sūkta is a sūkta of six Śloka from 34th chapter of Ṣukla Yajurveda. This hymn is dedicated to (a prayer) for having mind of Śiva (auspicious, good) Saṅkalpa (thoughts, intentions).
Fourth mantra read as follows:
येनेदं भूतं भुवनं भविष्यत् परिगृहिततममृतेन सर्वम् ।
येन यज्ञस्तायते सप्त होता तन्मे मनः शिवसंकल्पमस्तु ।।
yenedaṃ bhūtaṃ bhuvanaṃ bhaviṣyat parigṛhitatamamṛtena sarvam |
yena yajñastāyate sapta hotā tanme manaḥ śivasaṃkalpamastu ||
4 Whereby, immortal, all is comprehended, the world which is, and what shall be hereafter, Whereby spreads sacrifice with seven Hotars, may that, my mind, be moved by right intention.
As discussed in this answer there are mainly four types of group of ṛtvij (Vedic Priests) who accomplish the whole Yajna, Hotṛ, Udgātṛ, Adhvaryu and Brahma which recites hymns from Ṛg, Sāma, Yajur and Atharva Vedas respectively.
Here seven Hotā are mentioned. I want to know which those seven Hotās are.