Blockquote
“Mūlasarvāstivāda Vinaya would not perform legal acts together with monastics ordained according to the Sarvāstivāda Vinaya (or any other Vinaya), however much they might be holding the same doctrinal view.”
I took Refuge April 5th 1986 with a Lama and this means (I think) I remain belonging to a Mulasarvastivan nikaya even though I formally left that Sangha( do to cause) 
in 2009.
What acts are covered in the above quote from your PDF? Can I attend a Dharmagupta Uposada? 