Can BSI insert several dyes within an oligonucleotide?

Yes, if phosphoramidite version of the dye is available we can insert directly during the time of synthesis. Some dye require pos-synthetic conjugation we can either use amino modified base such as amino dT or artificially insert an amino modifier in between two base at sugar phosphate backbone.

Example below:

Oligo is inserted one dye in between two base

Oligo is inserted wto same dye:

Oligo is inserted thre same dyes